A method for Hybrid Automatic Repeat Request (HARQ) combination is disclosed. The method includes that: externally configured parameters relevant to HARQ combination are received, and an identifier ddr2switch of DDR2 switching is calculated to acquire addresses involved before and after the HARQ combination; it is determined, according to the parameters and the addresses involved before and after the HARQ combination, whether the HARQ combination is needed to be performed; and when it is determined that the HARQ combination is needed to be performed, data in a DDR2 are read and stored into a first data cache random access memory RAMA; and a HARQ combination calculation is performed, and the calculation result is stored into a second data cache random access memory RAMB. A device for HARQ combination is further disclosed. The technical solutions provided in the disclosure are based on a latest interference cancellation algorithm, greatly increase the success probability of decoding, saves the storage space of a DDR2 and improves the reading/writing efficiency.