Abstract: Objective To dynamically observe the serum levels of tumor necrosis factor-α(TNF-α),carcinoembryonic antigen(CEA) and carbohydrate antigen 242(CA242) before and after the surgery for rectal cancer(RC). To explore the clinical value of combined detection of TNF-α,CEA and CA242 for the diagnosis,valuing curative effect and illness monitoring for RC. Methods From January,2014 to June,2014,60 cases of rectal diseases(including 30 cases of RC in Group A and 30 cases of benign rectal disease in group B) and 30 cases of healthy adults(Group C) were enrolled into this study. The serum levels of TNF-α,CEA and CA242 were measured and compared among the three groups by using one-way analysis of variance. In group A,the serum levels of TNF-α,CEA and CA242 were measured one day before the surgery,five days after the surgery,ten days after the surgery and one month after the surgery were tested and analyzed by repeated measures analysis of variance. Results The serum levels of TNF-α,CEA and CA242 in group A were significantly higher than those in group B and group C,and there was significant difference between group A and group B or C(P < 0. 05). In addition,the serum levels of TNF-α,CEA and CA242 in group A were decreased after the surgical treatment and there was significant difference at different time points(P < 0. 05). Conclusion The serum levels of TNF-α,CEA and CA242 in most patients of RC are significantly elevated and the combined detection of serum TNF-α,CEA and CA242 contributes to the diagnosis,valuing curative effect and illness monitoring for RC.