Abstract: Keshan disease is an unexplained cardiomyopathy. It is traditionally believed that Keshan disease is related to the selenium lack or the excess of heavy metals in the soil. A land quality survey of black soil in the whole Keshan County shows that the content of soil selenium in this area is moderate. In the high incidence areas of keshan disease, however, there are selenium-rich soils and selenium-rich crops, which is contrary to the traditional understanding of the disease. This study provides new material and directions for further research into the Keshan disease.