Currently, a Chinese Visa is not enough to visit Tibet. You will also need several Tibet Permits, including Tibet Tourism Bureau Permit(TTB Permit), Alien Travel Permit(PSB Permit) and Military Permit which are issued by three different Tibet authority bureaus.Among these three permits,the TTB Permit is the most important one that you need to buy a flight or train ticket and board flight or train to Tibet. Besides,the TTB is needed to apply the following two permits: Alien Travel Permit and Military Permit.
TTB (Tibet Entry Permit): It is issued by Tibet Tourism Bureau and is a must for foreign tourists entering Tibet. When you check in your flight to Tibet, you have to showcase your original TTB Permit. While if you take a train into Tibet, only a copy of your TTB Permit is needed. The TTB Permit is your key to Tibet, please contact us to apply it.
PSB (Alien's Travel Permit): It is required when you are planning to travel to the remote areas in Tibet, which you can obtain it after you arrive in Tibet. PSB Permit can be issed in the capital city of each prefectures in Tibet by local Public Secuiry Bureau.
Military Permit: you have to obtain if you are planning to travel to some sensitive areas, for example - Nagri.