A service flow adjustment method and a communication apparatus are provided. Slot adjustment information is carried in a client signal flow sent between nodes, so that times at which all nodes on a network switch slot configuration can be unified, to avoid service damage in a process of adjusting a network transmission bandwidth. The method includes: A first node receives a first client signal flow from a second node by using N slots of a first bundling group; and after first duration starting from a time at which the first node detects slot adjustment information, the first node receives the first client signal flow from the second node by using M slots of the first bundling group.