Immunohistochemistry showed that CA-IX was expressed on the cell membrane, The positive rate of CA-IX in bladder urothelial carcinoma was 68.1% (132/194), the positive rate in adjacent tissues was 44.3% (86/194), and the positive rate in normal tissues was 27.3% (53/194). This evidence concerns the gene CA9 and bladder transitional cell carcinoma.