Objective To develop a light source system for the treatment of rectal cancer photodynamic therapy based on magnetic coupling resonant wireless power supply technology.Methods The proposed system consists of the implant and the external power supply device.The implant includes a light source and a resonant receiving coil.The light source is a 650 nm LED.The light source and the receiving coil were encapsulated with transparent epoxy to benefit the implantation and biocompatibility.The external power supply device was based on the magnetic coupling resonant technology,and the frequencies of the high frequency inverter and the natural frequency of the transmitting coil and the receiving coil were set at the same resonant frequency to ensure the efficient transmission of energy.Results The power density range of the light source is 3～22 mW/cm2 in the vertical distance range of 50～ 180 mm to the plane of the transmitting coil.Conclusions In the proposed light source system,the LED was separated from the power source.The size of the implant is small enough to be implanted,and the external power source can provide a real-time and stable energy supply for the implant.