An endemic heartdisease,which was called "Keshan Disease",has been noted in northeastern China.The soil associated with the disease which was described as the leaehed soil was mainly located on the rolling hills and mountains.In order to study the correlation between the selenium content of soil and "Koshan Disease" the content of trace element selenium in soils of this region was determined. It has been found that the total selenium content of soil in northeastern China varies from 0.015 to 0.540 ppm,with an average content of 0.108 ppm.The selenium content has a close relation with soil organic matter,the more the organic matter,the higher the selenium contains.