This study demonstrated that TGF‐β1 and Smad2 were highly expressed in bladder cancer tissues, and RT‐qPCR and Western blotting demonstrated that the mRNA and protein levels of TGF‐β1, Smad2 and p‐Smad2 increased in the TSP‐1, TGF‐β and TGF‐β + TSP‐1 groups, while they decreased in the GP73‐siRNA‐1 and GP73‐siRNA‐2 groups. This evidence concerns the gene SMAD2 and urinary bladder carcinoma.