In recent years, the wireless local networks are constructed rapidly and their coverage greatly increase. The passive radar imaging of moving targets using WiFi signals is studied in this paper, which may lead to wider applications of passive radars. Firstly, the ambiguity function of WiFi signals is analyzed. The results show that the WiFi signal has good range and velocity ambiguity and can be used as an illumination source. Then, distributed apertures are used to receive target echoes and the imaging is performed using a Generalized Likelihood Ratio Test (GLRT)-based approach. The positions and velocities of the moving targets can be reconstructed. The resolution of the imaging method is also analyzed. Simulation results demonstrate the performance of the presented passive radar imaging method of moving targets using WiFi signals.