In this study we explored the diagnostic value of joint detection of Thymidine Kinase 1(TK1), carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9) and carbohydrate antigen 72-4 (CA 72-4) in the diagnosis of CRC, and evaluated the relationship between TK1 expression and clinical pathological characteristics in the patients. The gene discussed is CEACAM5; the disease is colorectal carcinoma.