Objective:To compare the antitumor effect of paclitaxel-loaded liposomes with paclitaxel on S180 ascites-tumour bearing mice. Methods:The paclitaxel-loaded liposomes were prepared by reverse evaporation and sonication techniques. The particle diameters were measured by dynamic light scattering(DLS) measurement and the entrapment efficiency was measured by the reverse-phase high-pressure liquid chromatograph(RP-HPLC) method. Twenty Kunming mice bearing ascites tumor xenografts were distributed into four groups at random:the control,empty-liposomes,free paclitaxel group and the paclitaxel-loaded liposomes. Treatments were started after 24 hours of implantation. Two groups bearing S180 xenograft were treated i.p. with 10 mg/kg of paclitaxel(free drug or liposome encapsulated). The other two groups were given i.p. with saline or empty-liposomes. All the treatments were given 4 times and the interval was 72 hours. Results:The average diameter of the paclitaxel-loaded liposome was 282.4 ± 8.94 nm. The entrapment efficiency was 91%. There were resembly much ascites in the three groups of the control, empty-liposomes and free paclitaxel. While in the group of paclitaxel-loaded liposomes,there was little ascites. In addition,there were dramatically little metastasis in abdominal cavity with the group of the paclitaxel-loaded liposomes other than the remain three groups. Conclusion:Ascites and metastasis in abdominal cavity could be inhibited by paclitaxel-loaded liposomes to S180 ascites-tumour bearing mice remarkly.