A method for initializing communications network delay variation smoothing, comprising: clearing, by a receiving module of a local device, a forward delay threshold and a reverse delay threshold when an initialization time starts, wherein the forward delay threshold is used for delay compensation of a forward direction of a service flow, the forward direction of the service flow is a direction in which the service flow flows from a sending module of a peer device to the receiving module of the local device, the reverse delay threshold is used for delay compensation of a reverse direction of the service flow, the reverse direction of the service flow is a direction in which the service flow flows from a sending module of the local device to a receiving module of the peer device; determining, by the receiving module of the local device, a real-time forward delay value corresponding to a current service flow fragment, and receiving a reverse delay threshold that is corresponding to the current service flow fragment and is sent by the sending module of the peer device, wherein the real-time forward delay value refers to a delay of transmission of a service frame on a link of the communications network; when determining that a maximum value between the real-time forward delay value corresponding to the current service flow fragment and the reverse delay threshold corresponding to the current service flow fragment is greater than a current value of the forward delay threshold, replacing, by the receiving module of the local device, the current value of the forward delay threshold with the maximum value; and when determining that the initialization time has not ended, returning, by the receiving module of the local device, to performing obtaining of a real-time forward delay value corresponding to a next service flow fragment and a reverse delay threshold corresponding to the next service flow fragment. clearing, by a receiving module of a local device, a forward delay threshold and a reverse delay threshold when an initialization time starts, wherein the forward delay threshold is used for delay compensation of a forward direction of a service flow, the forward direction of the service flow is a direction in which the service flow flows from a sending module of a peer device to the receiving module of the local device, the reverse delay threshold is used for delay compensation of a reverse direction of the service flow, the reverse direction of the service flow is a direction in which the service flow flows from a sending module of the local device to a receiving module of the peer device; determining, by the receiving module of the local device, a real-time forward delay value corresponding to a current service flow fragment, and receiving a reverse delay threshold that is corresponding to the current service flow fragment and is sent by the sending module of the peer device, wherein the real-time forward delay value refers to a delay of transmission of a service frame on a link of the communications network; when determining that a maximum value between the real-time forward delay value corresponding to the current service flow fragment and the reverse delay threshold corresponding to the current service flow fragment is greater than a current value of the forward delay threshold, replacing, by the receiving module of the local device, the current value of the forward delay threshold with the maximum value; and when determining that the initialization time has not ended, returning, by the receiving module of the local device, to performing obtaining of a real-time forward delay value corresponding to a next service flow fragment and a reverse delay threshold corresponding to the next service flow fragment.