The invention discloses a network switching device. The device comprises a first detection module used for detecting wireless signal intensity of a mobile terminal connected with a wireless network at present; and a first starting module used for starting a mobile data network channel of the mobile terminal when the wireless signal intensity is detected to be smaller than a first preset threshold and last for a first preset time length. The invention further provides a network switching method. The network switching device and method is capable of helping a user automatically start the mobile data network channel of the mobile terminal when the wireless network connected with the mobile terminal has faults, is invalid or is poor in network state, thereby realizing network automatic switching, preventing the mobile terminal against network failures due to the unstable wireless network, ensuring that a user can surf the internet smoothly and stably, preventing the user from missing important network information and network notifications due to network problems, and improving the networking experience of the user.