Objective To observe the exact effect of microbubble-enhanced ultrasound cavitation combined with natural killer (NK) cells on microwave ablation of rabbit liver VX2 tumors. Methods Forty rabbits with VX2 liver tumors were randomly divided into five groups (eight animals per group): microwave ablation (MW), ultrasonic cavitation (CA), NK cell injection (NK), microwave ablation plus ultrasonic cavitation and NK cell injection (MW+CA+NK), and blank control (BL). Each group was administered their respective treatment intervention. Two-dimensional and contrastenhanced ultrasound imaging techniques were used to evaluate changes in tumor volume and maximum diameter 10 days after treatment. Tumor blood flow was evaluated by contrast-enhanced ultrasound imaging after treatment. Results Tumor volume and maximum diameter of the MW+CA+NK group were both significantly reduced compared with other groups 10 days after treatment ( P < 0. 05). In addition, blood flow of the MW+CA+NK group was significantly decreased compared with the other groups ( P < 0. 05). Conclusions Microbubble-enhanced ultrasound cavitation combined with NK cell could significantly enhance the effects of microwave thermal ablation of rabbit liver VX2 tumors.