Embodiments of the present invention provide a coding method and apparatus, a base station, and user equipment. The method includes: determining a quantity of polar codes used to code a to-be-transmitted data block and a block length of each polar code of the polar codes used to code the to-be-transmitted data block; and determining, according to a quantity of bits of the to-be-transmitted data block, the block length of each polar code of the polar codes used to code the to-be-transmitted data block, and an input composite channel characteristic corresponding to each input bit position in the polar code of the polar codes used to code the to-be-transmitted data block, allocation information of valid input bits of the polar code of the polar codes used to code the to-be-transmitted data block. The quantity of polar codes used to code the to-be-transmitted data block is not less than two.