The present disclosure relates to a SIM card sharing method and device, a communication device, and a storage medium. The SIM card sharing method applied to the first device may include: in response to the first device's requirement for obtaining cellular mobile communication, sending share request information to a second device through an interactive channel, where the interactive channel is established between the first device and the second device through a preset connection manner; receiving SIM card information that is returned by the second device based on the share request information; and establishing a cellular mobile communication connection with the base station according to the SIM card information.