Systematic experiments about the antitumor effects of low energy laser irradiation combined with the traditional antitumor medicine of cyclophosphamide were conducted using the experimental model of mouse S180 ascites sarcoma.The three groups of tumor bearing mice were irradiated upon the inner corners with the dosages of 11 00,14 67 and 22 00 J·cm -2 LELI respectively,and injected with CYT intraperitoneally to observe the changes of the survival time,the ascites growth speed,and the kinetic changes of immune functions.The survival times of the three groups of CYT/LELI combination were obviously longer than those of the tumor and CYT control groups.Correspondingly,the amounts of ascites,tumor cells densities and total tumor cells in CYT/LELI groups decreased significantly,while the death ratio of the tumor cells increased.Comparatively,the group of 22 00 J·cm -2 LELI combined with CYT showed the most ideal antitumor effects,and the life prolongation ratio was up to 53 20%. Systematic experiments about the antitumor effects of low energy laser irradiation combined with the traditional antitumor medicine of cyclophosphamide were conducted using the experimental model of mouse S180 ascites sarcoma. Three groups of tumor bearing mice were irradiated upon the inner corners with the dosages of 11 00 , 14 67 and 22 00 J · cm -2 LELI respectively, and injected with CYT intraperitoneally to observe the changes of the survival time, the ascites growth speed, and the kinetic changes of immune functions. The survival times of the three groups of CYT / LELI combination were obviously longer than those of the tumor and CYT control groups. Correspondingly, the amounts of ascites, tumor cells densities and total tumor cells in CYT / LELI groups decreased significantly, while the death ratio of the tumor cells increased.Comparatively, the group of 22 00 J · cm -2 LELI combined with CYT showed the most ideal antitumor effects, and the life prolongation ratio was u p to 53 20%.