The present disclosure provides an auxiliary communication method and system, a device having base station function and a terminal. The auxiliary communication method includes: determining whether it is needed to provide auxiliary communication for any terminal according to channel quality of communication channels with the any terminal and data transmission requirement of the any terminal; selecting a specified terminal which is connected to the device having the base station function as an auxiliary terminal for assisting communication of the any terminal, when it is determined that it is needed to provide auxiliary communication for the any terminal; communicating with the any terminal through the auxiliary terminal. The present disclosure enables accurately to determine the terminal assisted in communication. Wasting communication sources and blind assistance are avoided. And higher channel quality of the terminal between the terminal and the base station and higher data transmission rate can be ensured.