This paper describes the kidney microstructure of Rana nigromaculata. Histological and histochemical observation showed that besides nephrons and collecting tubes, lymphoid tissues could be observed in the kidney. Moreover,a structure that was similar to the corpuscle of Stannius of teleost was found at the ventral side of the kidney. Numerous mast cells could be observed in that structure as well,suggesting that the kidney of R. nigromaculata is a multifunctional organ.