Abstract：This paper introduces in detail the method of assessing China’s tin resources potential by using the geochemical block concept and the results of RGNR. It gives the calculation formulas for determination of the metal endowment, geochemical block mineralization coefficient, resource and potential resource. And a correction coefficient is used in calculating the metal endowment in geochemical blocks according to the metal content in stream sediments. The paper also describes the characteristics of the spatial distribution of China’s Sn geochemical blocks and analyzes the spatial relationships of these blocks with geological bodied and known Sn deposits. The Sn geochemical block mineralization coefficients at the 8×10-6 and 10×10-6 concentration levels in China are 0.205% and 0.208% respectively. According to the distribution and features of the Sn geochemical blocks outlined on the continent of China and by using the two mineralization coefficients, China’s potential Sn resources are estimated to be about 16.09 million tons and 14.06 million tons respectively.