Abstract: Objective To explore whether sonoflora， a sonosensitizer， can accumulate selectively in the S180 sarcoma of mice and to assess its antitumor effects of sonodynamic therapy（SDT）. Methods S180 sarcoma tumorbearing mice received intraperitoneal injection of 10mg／kg of sonoflora and were respectively sacrificed on 3h， 6h， 12h， 18h， 24h， 48h， 72h. Sonoflora gathered in the tumor and normal muscle tissues was observed by confocal microscopy. Tumorbearing mice were treated with ultrasound， sonoflora and ultrasound combined with sonoflora treatment， respectively. The blank control group was received intraperitoneal injection of saline solution. Tumor size was measured every 2 days and then tumors were stripped for weight comparison on 15th day. Results The sonoflora content of the tumor tissues was 5.33 times higher than that of the normal muscle tissues at its peak at the 18th hour after intraperitoneal injection， and the difference was the most obvious. It was the best time for SDT. Ultrasound alone（0.4W／cm²， 0.8W／cm²， 1.6W／cm²）or sonoflora alone（10mg／kg，20mg／kg，40mg／kg）had exhibited no significant effects on tumor size and tumor weight. The weight of tumor tissues in sonoflora（10mg／ml）combined with ultrasound with 0.4W／cm²（S1U1），0.8W／cm²（S1U2），1.6W／cm²（S1U3）were （2.30±0.40）g，（0.94±0.44）g and （0.88±0.28）g，respectively. The weight of tumor tissues in S1U1, S1U2 and S1U3 was less than that of control group，ultrasound alone and sonoflora alone group. There were significant statistical differences（P＜0.05）. The weight of tumor tissues in S1U1 group had statistical differences from that of S1U2，S1U3 group（P＜0.05）. There were no statistical differences between S1U2 and S1U3 group（P＞0.05）. Conclusion Sonoflora has the ability of special accumulation targeting to tumor， and ultrasound combined with sonoflora has significant damaging effect on S180 sarcoma.