Objective To determine the influence and significance of combinative assessment of 64 multi-slice spiral computer tomography (MSCT) with serum amyloid A protein (SAA) or fibrinogen (FIB) on the selection of operative procedures of rectal cancer under the multidisciplinary team. Methods Prospectively enrolled 240 patients diagnosed definitely as rectal cancer at West China Hospital of Sichuan University from February to June 2009 were randomly assigned into two groups. In one group named MSCT+SAA group, both MSCT and SAA combinative assessment were made for the preoperative evaluation. In another group named MSCT+FIB group, both MSCT and FIB combinative assessment were made for preoperative evaluation. Furthermore, the preoperative staging and predicted operation procedures were compared with postoperative pathologic staging and practical operation procedures, respectively, and the relationship between the choice of operation procedures and clinicopathologic factors was analyzed. Results According to the criteria, 234 patients were actually included into MSCT+SAA group (n=118) and MSCT+FIB group (n=116). The baseline characteristics of two groups were statistically similar (Pgt;0.05). For MSCT+SAA group, the accuracies of preoperative staging T, N, M and TNM were 72.9%, 83.1%, 100% and 80.1%, respectively. For MSCT+FIB group, the accuracies of preoperative staging T, N, M and TNM were 68.1%, 75.0%, 100% and 74.1%, respectively, and there was not a statistically significant difference (Pgt;0.05). There was also not a statistically significant difference of the accuracy of prediction to operative procedures in two groups (99.6% vs. 96.6%, Pgt;0.05). The preoperative T staging (P<0.001), N staging (P<0.001), TNM staging (P<0.001), serum level of SAA (P<0.001), serum level of FIB (Plt;0.001) and distance of tumor to the dentate line (P<0.05) were associated to the operative procedures. Conclusions Combinative assessment of MSCT and FIB could improve the accuracy of preoperative staging and operative procedures prediction, however, it may be not superior to MSCT plus SAA.