Objective In the treatment of tumor with high intensity focused ultrasound (HIFU),the acoustic pressure distribution determines the safety and reliability of HIFU.It is necessary to predict the acoustic field produced by HIFU transducer.Methods To analyze the acoustic pressure distribution of HIFU generated by different excitation frequency and variable incentive power,comparison was made between the acoustic pressure simulated by finite difference time domain (FDTD) method and the ones measured by experiments.ResultsThe resultsshowed that the pressureat focalpoint increasedwiththe increasing of excitation power,while the change in the focal length was negligible.The focal point moved towards the transducer with the frequency increasing until the maximum sound pressure was gained at the resonant frequency (RF).Conclusion The simulation results are consistent with the experiment results,indicating that the acoustic fields can be predicted by simulation.