To investigate the expression and clinical value of serum TPS(tissue polypeptide specific antigen) assay in patients with gastrointestinal tract tumor. Fifty six patients with gastrointestinal tract tumors were studied in contrast with 114 healthy people. The levels of serum TPS, CEA, and CA199 were assayed with ELISA. The results showed that the levels and positive rates of serum TPS, CEA and CA199 were significantly higher in gastrointestinal tract tumor group than those in the normal healthy group ( P