Abstract： Objective To investigate the anti-tumor effect of ultrasound-targeted microbubble destruction (UTMD) mediated herpes simplex virus thymedine kinase (HSV-TK) on mice ovarian cancer.Methods Forty female BALB/c-nu mice were randomly divided into four groups after the models of subcutaneous transplantation tumors were established:(A)HSV-TK + Microbubbles + Ultrasound (HSV-TK+ MBs + US);(B) HSV-TK+ Ultrasound (HSV-TK + US);(C) HSV-TK;(D) PBS.TheTK protein and mRNA expression were separately detected by western-blot and real time RT-PCR.TUNEL staining was used to detect the tumor cell apoptosis.The inhibition rates and survival time of the animals were compared among all groups.Results The HSV-TK gene transfection efficacy and tumor inhibitory effect of HSV-TK on mice transplantable tumor in group A (HSV-TK + MBs + US) were significantly improved compared with group B (HSV-TK + US),group C (HSV-TK) and group D (PBS) (P ＜0.05).However,group A has no significant difference (P ＞0.05) with other groups in improving the survival time of tumor-bearing mice.Conclusions Ultrasound-targeted microbubble destruction can effectively transfect HSV-TK gene into target tissues and play a significant inhibition effect on ovarian cancer in mice.However,this new method is not able to improve the survival time of mice for a short-term observation.