A low power IC of bi-directional wireless monitoring system for orthopedic implants was designed,which was powered by stiff lead zirconate titanate(PZT) ceramics and radio frequency signal.The analog/digital mix-mode system monitors the implant duty cycle,detects abnormal asymmetry,wear,high amounts of force and other conditions of the orthopedic implants.Data for diagnosis from sensors were converted into digital signals and saved in the memory.Communication between the embedded chip(inside body) and the remote circuit (out sidebody) was made wirelessly through RF signals. RF circuit s were taped out and tested , and satisfactory result was achieved. And the power circuit was also simulated for verification.