Under the funding of the NSFC, MOST 973 Project and Sino-Canada Joint Program, mercury in the Namco Lake basin was studied for the transportation and transformation mechanism in the cryospheric environment on the Tibetan Plateau. The field work, conducted from July 11 to 25, 2009, included sampling of mercury in various environmental proxies as in snow/ice, lake water and lake sediment core, and fish bodies. In particular, five vertical profiles in the Namco Lake were chosen for sampling at an interval of 4 meters over the lake with depth varying from 16m to 96m underwater, in an effort to reveal the spatial contrast of total mercury, TOC, microbes and water quality parameters (eg., PH, DO etc) from west to east and from south to north. In the processing and analysis of samples acquired during the field trip, volume of mercury and other trace heavy metal accumulated in the biosphere in the Namco Lake basin will be further studied, so as to help formulate a model of mercury in the biogeochemical cycle over the region.