OBJECTIVE: To establish the method of quality control for traditional Tibetan Medicine Zsuotai.METHODS: Collecting the samples of Tsuotai from Qinghai, Tibet, Sichuan, and Gansu province, to detect Hg2+ by Zsuotai reacted with HCl-HNO3 (3:1), and to determine the quantity of HgS in Zsuotai by sulfocyanate volumetric method. RESULTS: The method for the determination of HgS in Zsuotai was in good reproducibility (RSD = 0.68%). The calibration curve was linear (r = 0.9999) within -0.0002 - 0.2123 g of mercuric sulfide. The recovery was 100.94% (RSD = 0.66%). CONCLUSIONS: This method is convenient and accurate, so it can be used to establish quality control of the medicinal material.