Chinese Visa

Firstly, please be noted that Chinese visa and Tibet permit are two things totally different. To enter Tibet, or any part of China excepting Hong Kong and Macao (Visitors to Hong Kong, holding passports from some countries DO NOT need a visa when staying for a specified free period), a Chinese visa is necessary. It may be best to obtain it before leaving your home country unless you are taking a package tour to enter Tibet overland from Nepal.

A tourist visa, is marked with "L" in the many kinds of Chinese visas. Visa L is characterized by a short duration of stay, usually 30 days, no more than 90 days, and could not be extended upon expiration.

Group visa, another kind of tourist visa, is applied by foreigner traveling in tour groups. Group visa is not issued on the passports, but on a separate paper, which requires the group members enter and exit the Chinese border together.

From Nov. 15th 2000, aliens traveling to Hong Kong and Macao Special Administrative Regions(SAR) in tour groups organized by travel agencies registered in the above-mentioned SARs are exempted from visa requirements for a period not exceeding 6 days when entering into the following Chinese mainland cities: Guangzhong, Shenzhen, Zhuhai, Foshan, Dongguan, Zhongshan, Jinangmen, Zhaoqing, Huizhou,etc. The premise is that the traveler shall have the citizenship of a country having diplomatic relations with the People's Republic of China and carrying an ordinary passport.

If you are coming to Lhasa from Kathmandu, you'd better get China visa from Kathmandu because whether you've already got the visa in your country or not, you must get a visa in Kathmandu, which is regulated in an official memo between China and Nepal.

The first rule when applying for a visa as an independent traveler is to expect that you will be refused a visa if you mention plans to visit Tibet. There is a trick that when you apply for the Chinese visa, you can't tell the officer that you have the plan for traveling to Tibet; you can only inform them you want to travel to somewhere else of China. Or else the application would become complicated and arduous.

Keep in mind 

1. When entering China it is best to have a visa covering the expected duration of stay. Getting extensions inside China can involve delays and other difficulties. 

2. You need to apply for a double or multiple entry visa when you need to leave and re-enter mainland China. Please note that, even when you leave for Hong Kong or Macao from mainland China, you still need to have a double- or multiple entry visas.

What kind of Chinese Visa can be issued Tibet Permit?

A Chinese visa is a permit issued by the Chinese visa authorities to an alien for entry into, exit from or transit through China. The Chinese visa authorities may issue a Diplomatic, Courtesy, Official or Regular Visa to an alien according to his/her status, purpose of visit to China or passport type.

The overseas Chinese visa authorities are Chinese embassies, consulates, and other offices authorized by the Ministry of Foreign Affairs of China. If a foreigner intends to enter into, exit from or transit through Chinese territory, he/she shall apply for a Chinese visa to the above-mentioned Chinese visa authorities .

Here Tibettravel.org will give you the main type of Visa concerning with Tibet Tour and the attached document for Tibet Permit application.

Visa-free entry into China

Visa-free entry for visitors: No visa is required for ordinary passport holders from Singapore, Brunei and Japan to visit China for up to 15 days for business, sightseeing, visiting relatives and friends or transit.
Documents for Tibet Permit: Photocopy of passport in large size,Tour Itinerary

Regular Visa

Regular Visas consist of 5 sub-categories which can be issued Tibet Permit, Here are respectively marked with Chinese phonetic letters D, F, L, X and Z.

D Visa: Issued to an alien who comes to reside permanently in China.
Documents for Tibet Permit: Photocopy of passport in large size,Tour Itinerary, Working Permit, Residence Permit.

F Visa: Issued to an alien who is invited to China for a visit, an investigation, a lecture, to do business, scientific-technological and culture exchanges, short-term advanced studies or internship for a period of no more than six months.
Documents for Tibet Permit: Photocopy of passport and Chinese visa in large size,Tour Itinerary, Any documents to prove you are temporarily working in China or are invited by any company in China for the purpose of working, visiting, learning.

Please notice that, although you hold a F Visa, you are invited by the government department, Tibettravel.travel do not accept your application, please contact with the government to get the special Tibet visiting admission.

L Visa: Issued to an alien who comes to China for sightseeing, family visiting or other private purposes.
Documents for Tibet Permit: Photocopy of passport and Chinese visa in large size, Tour Itinerary.

X Visa: Issued to an alien who comes to China for study, advanced studies or internship for a period of more than six months.
Documents for Tibet Permit: Photocopy of passport and Chinese visa in large size,Tour Itinerary, Any documents copy to prove you are temporarily working or studying in China, like student card, the paper from your school to certificate you are learning here.

Z Visa: Issued to an alien who comes to China for a post or employment, and his or her accompanying family members.
Documents for Tibet Permit: Photocopy of passport and Chinese visa in large size,Tour Itinerary, Any documents copy to prove you are temporarily working or studying in China, like student card, the paper from your school to certificate you are learning here.