Abstract: Acoustic cavitation induced by high intensity focused ultrasound (HIFU) can accelerate the thermal ablation of the target tissue. However, real-time monitoring of acoustic cavitation caused by HIFU is an urgent problem to be solved. The phase characteristics of the electrical signal of the HIFU transducer are established to analyze the real-time monitoring of acoustic cavitation. Under different HIFU excitation voltages, experimental research about real-time monitoring of acoustic cavitation in isolated bovine heart tissue irradiated by HIFU has been carried out. In addition, the phase difference of driving electrical signal is compared with the grayscale change of the B-ultrasound image and change results of subharmonic and broadband noise detected by broadband hydrophone. The research results show that when acoustic cavitation occurs, the change of phase difference of driving electrical signal has good consistency with the change of subharmonic and broadband noise detected by hydrophone. By the change of phase difference, real-time and accurate monitoring of the duration of acoustic cavitation occurring in target tissue irradiated by HIFU can be achieved, which provides a promising solution for real-time monitoring of acoustic cavitation caused by HIFU.