Provided in the embodiments of the present application are a wireless communication method, a first device, and a second device. The method comprises: determining the number of retransmissions of a first physical channel; performing counting on the basis of multiple available time domain units corresponding to the first physical channel, to obtain a count of each available time domain unit; and on the basis of the number of retransmissions and the count of each available time domain unit, sending duplication data of the first physical channel. The method provided by the present application can ensure that count results obtained by a network device and a terminal device for available time domain resources maintain consistency, thereby facilitating the improvement of the decoding performance, and also facilitating a network side and a terminal side having consistent understanding of an RV version corresponding to each transmission in retransmission, thus improving the quality of communication.