A device-to-device, D2D, relay communication method, comprising: receiving, by a first terminal, indication information sent by a second terminal, wherein the indication information is used for indicating information of a network on which the second terminal currently resides; and determining, by the first terminal, whether the first terminal and the second terminal reside on a same network according to the indication information, receiving, by the first terminal, the indication information sent by the second terminal, comprises: receiving, by the first terminal, a first message sent by the second terminal, wherein the first message comprises the indication information, and the first message is a Discovery Announcement message or a direct communication message, wherein the information of the network on which the second terminal currently resides comprises time consistency information, if the time consistency information indicates that the network on which the second terminal resides does not change within a specific time period, the first terminal directly determines, within the specific time period, the network on which the second terminal resides without receiving indication information sent by the second terminal any more within the specific time period, and determines the network on which the second terminal currently resides through the indication information. receiving, by a first terminal, indication information sent by a second terminal, wherein the indication information is used for indicating information of a network on which the second terminal currently resides; and determining, by the first terminal, whether the first terminal and the second terminal reside on a same network according to the indication information, receiving, by the first terminal, the indication information sent by the second terminal, comprises: receiving, by the first terminal, a first message sent by the second terminal, wherein the first message comprises the indication information, and the first message is a Discovery Announcement message or a direct communication message, wherein the information of the network on which the second terminal currently resides comprises time consistency information, if the time consistency information indicates that the network on which the second terminal resides does not change within a specific time period, the first terminal directly determines, within the specific time period, the network on which the second terminal resides without receiving indication information sent by the second terminal any more within the specific time period, and determines the network on which the second terminal currently resides through the indication information. receiving, by the first terminal, a first message sent by the second terminal, wherein the first message comprises the indication information, and the first message is a Discovery Announcement message or a direct communication message, wherein the information of the network on which the second terminal currently resides comprises time consistency information, if the time consistency information indicates that the network on which the second terminal resides does not change within a specific time period, the first terminal directly determines, within the specific time period, the network on which the second terminal resides without receiving indication information sent by the second terminal any more within the specific time period, and determines the network on which the second terminal currently resides through the indication information.