This paper introduces a wireless radio frequency energy harvesting system to harvest the low-power RF signal in the environment. The system is mainly composed of antenna, matching circuit, and voltage doubled rectifier. To improve the system efficiency, a mathematical model of low input voltage doubled rectifier system based on diode is proposed. In order to match the antenna impedance with the input impedance of the rectifier, using the quantum particle swarm optimization algorithm to optimize the matching circuit parameters. Finally, the various simulation experiments are taken to test the feasibility of system design and optimization method. Simulation results show that the proposed RF energy harvesting system can improve the collection efficiency of RF signal.