The present invention provides a virtual SIM card implementation method, device, SIM server and terminal. The method includes: receiving a request message for applying for a virtual SIM sent by a terminal; allocating SIM information according to the request message, where the SIM information includes an international mobile subscriber identity code; performing network registration according to the SIM information; User parameters allocated by the network side device, the user parameters include a temporary mobile subscriber identity code and a key; the user parameters and the international mobile subscriber identity code are sent to the terminal. In the present invention, after the SIM information is allocated by the SIM server, the SIM server can directly perform network registration, obtain the temporary mobile user identification code and key allocated by the network, and then the terminal can directly use the temporary mobile user identification code and key for subsequent registration, A new authentication process can be avoided, thereby reducing the dependence on the data path in the virtual SIM card registration process, and improving the virtual SIM card registration success rate.