A node synchronization method, comprising: receiving, by user equipment UE, a notification message sent by a first node, wherein the notification message is used to instruct the UE to assist a second node to implement synchronization with the first node; receiving, by the UE, a downlink message sent by the first node; sending, by the UE, a random access message to the first node; and receiving, by the UE, a timing advance T1 sent by the first node, wherein the timing advance T1 is a timing advance of time of sending an uplink signal against time of arrival of a corresponding downlink signal at the UE, wherein the uplink signal is sent by the UE to the first node, and the corresponding downlink signal is sent by the first node to the UE; receiving, by the UE, a downlink message sent by the second node; sending, by the UE, a random access message to the second node; and receiving, by the UE, a timing advance T2 sent by the second node, wherein the timing advance T2 is a timing advance of time of sending an uplink signal against time of arrival of a corresponding downlink signal at the UE, wherein the uplink signal is sent by the UE to the second node, and the corresponding downlink signal is sent by the second node to at least one UE; calculating, by the UE, a timing offset between the first node and the second node according to at least a moment t1 of receiving the downlink message sent by the first node, a moment t2 of receiving the downlink message sent by the second node, the timing advance T1, and the timing advance T2, and sending, by the UE, the timing offset to the first node or the second node. receiving, by user equipment UE, a notification message sent by a first node, wherein the notification message is used to instruct the UE to assist a second node to implement synchronization with the first node; receiving, by the UE, a downlink message sent by the first node; sending, by the UE, a random access message to the first node; and receiving, by the UE, a timing advance T1 sent by the first node, wherein the timing advance T1 is a timing advance of time of sending an uplink signal against time of arrival of a corresponding downlink signal at the UE, wherein the uplink signal is sent by the UE to the first node, and the corresponding downlink signal is sent by the first node to the UE; receiving, by the UE, a downlink message sent by the second node; sending, by the UE, a random access message to the second node; and receiving, by the UE, a timing advance T2 sent by the second node, wherein the timing advance T2 is a timing advance of time of sending an uplink signal against time of arrival of a corresponding downlink signal at the UE, wherein the uplink signal is sent by the UE to the second node, and the corresponding downlink signal is sent by the second node to at least one UE; calculating, by the UE, a timing offset between the first node and the second node according to at least a moment t1 of receiving the downlink message sent by the first node, a moment t2 of receiving the downlink message sent by the second node, the timing advance T1, and the timing advance T2, and sending, by the UE, the timing offset to the first node or the second node.