Purpose: To investigate the antitumor effects of the angiogenesis inhibitor bevacizumab combined with chemotherapy, and the application of in vivo imaging technology of growth of fluorescence-labelled gastric cancer (GC) in nude mice. Methods: Twenty-five nude mice were randomly divided into 5 groups (A-E). Subcutaneous xenograft of human MGC803 cells was transplanted to nude mice, followed by different treatments for the groups, including A (bevacizumab combined with chemotherapy), B (24-h chemotherapy with FP followed by bevacizumab), C (bevacizumab 24-h followed by FP chemotherapy), D (bevacizumab only) and E (normal saline). Then, dynamic variation of tumor growth during 4 weeks was evaluated by calculating the tumor inhibition rate and fluorescence signal strength by in vivo imaging system. Results: After 28-day treatment, fluorescence signal strength in the groups A-D changed significantly compared with the E (control) group, while tumor inhibition rate in C group was highest (68.42%). Furthermore, on the 4th week, the fluorescence signal value in C group was lowest. Conclusions: Administration of bevacizumab followed by chemotherapy was more effective therapeutic method for GC. The in vivo imaging could show off dynamic variation of tumors and was a sensitive and objective detection method.