I hear that pass in Kulma Pass on Tajikistan-China border is closed for foreigners since 2008 (caused by Olympics).
Is it still closed? Is there any other pass between Tajikistan and China?
There is no other pass from Tajikistan directly to China which is open to tourists on the Chinese side of the border. The suggestion is generally to use Kyrgyzstan for land crossings, however, the border between Kyrgyzstan to Tajikistan is currently closed.
The other possibility is to use Uzbekistan as a intermediate point and then travel to Kazakhstan or Kyrgyzstan and then to China, but it will be the long way around.
Similar info about the Qolma crossing from Lonely Planet.