The invention belongs to the field of channel encoding, and particularly relates to a polar code coding and decoding method with segmented cyclic redundancy check (Cyclic Redundancy Check, CRC) auxiliary check. According to the polar code coding and decoding method provided by the invention, certain information bits are sacrificed to check polar codes to improve the decoding performance, and assuming that the length of used CRC is K-k bits, the information is averagely divided into M segments by segmented CRC check, k / M bits of information and (K-k) / M bits of CRC check information constitute an information structure of each segment, as shown in Fig.2. The information bits are encoded and transmitted by a channel, finally, SCL decoding and check are carried out on the information received by a receiving end, and L maximum storage paths are available. The polar code coding and decoding method provided by the invention can be used for shortening the time delay, bringing great convenience for real-time communication, saving the memory space of a register and providing great convenience for hardware realization.