Abstract: Objective To study the effects of chlorophyll-carotene paste from pine needles on tumor growth and its synergism with cyclophosphamide therapy and impact on immune function in mice inoculated with S180 tumorous cells to supply experimental data for its further development. Methods Sarcoma S180 tumor-bearing mice administered chlorophyll-carotene paste from pine needles(400,600,800 mg/kg)alone or combined with cyclophosphamide, tumor inhibitory rate and the immune function were detected by measuring of organ coefficient,serum half hemolysis value and phagocytosis clearance capacity. Results Chlorophyll-carotene paste from pine needles significantly inhibited the tumor growth in middle-dose and high-dose groups(P<0.05,P<0.01) and indicated apparente synergy effects with cyclophosphamide in low-dose and middle-dose groups(P<0.05,P<0.01).Chlorophyll-carotene paste from pine needles significantly improved serum half hemolysis value (P<0.01),clearance index K and phagocytic coefficient α (P<0.05) in tumor-bearing and cyclophosphamide-treated mice. Conclusion Chlorophyll-carotene paste from pine needles could inhibit the growth of the tumor and improve chemotherapeutic effects of cyclophosphamide which may be related to its reinforcement of the immune function.