Abstract: There two genetic types of mercury distribution in coal seams of Laochang mining area in eastern Yunnan: continentel deposit （A） and addition of epigentic mineralization（B）. The richness in the latter is remarkably higher than that in the former. In the low-sulfur coal, the predominant carrier of mercury is clay mineral. In the high-sulfur coal, the primary carrier of mercury is pyrite. The organic mercury concentration is lower. With the increase of pyrite content in coal and mercury concentration, it increases also. Based on the analytic data, mercury richness distribution in various coal seams with different distribution types is calculated. The wash-out possibility of mercury in coal has been preliminary evaluated.The average mercury concentration of exhaust gas in thermal power plant has been also forecasted in this paper.