A network switching method, device and system for mobile multimedia services are provided. The method includes: detecting signal strength of media stream data of a first network, and when the signal strength of the media stream data of the first network is smaller than a first preset value, receiving media stream data of a second network in parallel; and buffering the media stream data of the second network, decoding the buffered media stream data of the second network, and playing the decoded media stream data of the second network. The device includes a first communication module, a detecting module, a switching module, a second communication module, a processing module and a playing module. The system includes a first network, a second network and a terminal. Through the method, device and system, the time delay in the process of switching the serving network is reduced, and the service interruption caused by the network switching when the terminal performs multimedia services is prevented.