Objective To observe the chronological and spatial expressions of transforming growth factorβ receptor typeⅡ（TGF-βRⅡ）and fibronectin (Fn )in developing mouse kidney and investigate the relationship between the expressions and kidney development. Methods Immunohistochemistry and Western blotting were used to observe and measure the expression of TGF-βRⅡ and Fn in embryos and postnatal mouse kidneys. Results The expression of TGF-βRⅡ was noticed in all stages of glomeruli, renal tubes and collecting ducts, and increased gradually with ages; The expression of Fn was noticed too in all stages of glomeruli, renal tubes and collecting ducts, except for the c