The aim of this study was to study the distribution of Selenium (Se) and Mercury (Hg) in feed and drinking water in Heilongjiang Province and the effect on body of beef cattle.The experiment selected four areas of Qiqihar,Hmbin,Jixi and Hegang Cities in Heilongjiang Province.In each area,a pasture was selected.Five beef cattle from each ranch were collected.At the same time,blood,liver,muscle,kidney,urine and faece of the cattle were collected,as well as drinking water,feed and formula feed from the ranch.The contents of Se and Hg in the collected samples were detected by inductively coupled plasma mass spectrometry.The results showed that the contents of Se in liver,kidney,urine and blood of beef cattle were increased with the increase of Se contents in drinking water,while the contents of Se in muscle tissue and manure were decreased.When the contents of Se in feed increased,the contents of them in muscle,manure and liver of beef cattle were increased first and then decreased,while the contents of Se in kidney,urine and blood were decreased first and then increased.When Hg contents in drinking water were increased,the contents of them in beef cattle tissue,blood and manure were increased first and then decreased,and the contents of Se in urine were increased first and them decreased.And when Hg contents in feed increased,the contents of Se and Me were also increased.In conclusion,Se and Hg contents in these areas were within the safety standards,meanwhile,the contents of Se and Hg in body tissues of beef cattle were affected to varying degrees by the contents of selenium and mercury in feed.