This application discloses an information processing method, an apparatus, a communication device, and a communication system. The communication device is configured to determine a redundancy version transmission sequence, where the redundancy version transmission sequence is used to indicate a sending sequence of a plurality of redundancy versions; determine a transmission number; and obtain a redundancy version from a buffer sequence based on the redundancy version transmission sequence and the transmission number and send the redundancy version. The communication device may be applied to a communication system supporting a plurality of redundancy version transmission sequences, for example, a 5th generation (5G) communication system. Because the redundancy version transmission sequence is determined before data transmission, communication efficiency is improved, and HARQ performance is improved.