(1) With polyacrylamide gel electrophoresis, the LDH isozymes of 333 individuals of Rana chensinensis were analyzed, the frogs were sampled from four geographic population in Shanxi province, P.R. China. The results indicated that the LDH isozymes of Rana chensinensis are determined by three genes, they are LDH-A, LDH-B, LDH-C, LDH-A is a monomorphic locus, both LDH-B and LDH-C are polymorphic loci and each locus has two alleles, respectively. LDH-B links with LDH-C closely, it is assumed that LDH-C was produced by duplication of LDH-B. (2) Studies on the thermalstability, urea sensitivity and specific distribution in tissues showed that the order of LDH isozymes stability for heat and urea treatment is A4 > B4 > C4. A4 is abundant in skeleton muscle and B4 predominant in heart muscle and ovary. LDH-C expresses specifically in eye and ovary. (3) Ldh-b and Ldh-b' distribute differently in different geographic populations, with the increase of latitude, the frequence of Ldh-b becomes greater in population.