The monastery is famous throughout Tibet since it was the first Buddhist chapel ever built in Tibet. It lies five kilometers (three miles) south of Tsedang on the road leading to Yumbu Lakhang. Built approximately under the reign of Songtsen Gampo, Trandruk later experienced large-scale reconstruction after it converted to Gelugpa. Legend said that it was only after Songtsen Gampo turned into a roc to conquer an evil dragon that it could be built there, which is the origin of its name, meaning a roc conquering a dragon. Songtsen Gampo and Princess Wencheng always visited the monastery after they moved to Lhasa. An apartment believed to be their lodgings during their visits in Trandruk is still left, however restoration is badly needed since it is in poor condition. Princess Wencheng left many willow trees around the monastery.

The main building in Trandruk is its Tshomchen, in which Padmasambhava is enshrined. The Jokhang like building has many chapels, in one of which a precious pearl Thangka, representing Chenrezi in rest, is housed. The Thangka is made of about 30,000 pearls and hundreds of other gems like diamond, sapphire, turquoise, ruby and amber. Pilgrims throw money to the thangka to show their respect.