A communication method applied to an integrated access and backhaul (IAB) system includes: a child node receives a first radio resource control (RRC) reconfiguration message from an access network device via a parent node, where the first RRC reconfiguration message includes a random access-free indication. The child node starts a timer. The child node sends a first RRC reconfiguration complete message to the access network device via the parent node. The child node receives first indication information from the parent node, where the first indication information indicates to stop the timer. The child node stops the timer.