A method for message processing between communications systems, comprising: acquiring (303; 403), by a centralized controller, a first report message of an operation event in a source system, wherein the first report message comprises a first user equipment identifier; acquiring (305; 405), by the centralized controller, a second report message of the operation event in a target system, wherein the second report message comprises a second user equipment identifier wherein the operation event is redirection or handover between the source system and the target system and wherein the source system is a LTE system or an UMTS or GSM system; the target system is a LTE system or an UMTS or GSM system; and the source and the target systems are different; and determining (306; 408), by the centralized controller, that a first user equipment identifier is consistent with a second user equipment identifier, and determining whether a time interval between the acquiring of the first report message and the acquiring of the second report message is less than a preset valid time, and if the time interval is less than the preset valid time, correlating (307, 409), by the centralized controller, the first report message with the second report message according to the first user equipment identifier and the second user equipment identifier, and performing, by the centralized controller, event statistics collection related to the correlated first report message and second report message, wherein the determination whether the first user equipment identifier is consistent with a second user equipment identifier includes using a mapping rule that allows a mapping between different user equipment identifier types used in different systems, wherein, when the first user identifier is consistent with the second user identifier, the centralized controller indicates that the operation event is an operation event of the same user equipment. acquiring (303; 403), by a centralized controller, a first report message of an operation event in a source system, wherein the first report message comprises a first user equipment identifier; acquiring (305; 405), by the centralized controller, a second report message of the operation event in a target system, wherein the second report message comprises a second user equipment identifier wherein the operation event is redirection or handover between the source system and the target system and wherein the source system is a LTE system or an UMTS or GSM system; the target system is a LTE system or an UMTS or GSM system; and the source and the target systems are different; and determining (306; 408), by the centralized controller, that a first user equipment identifier is consistent with a second user equipment identifier, and determining whether a time interval between the acquiring of the first report message and the acquiring of the second report message is less than a preset valid time, and if the time interval is less than the preset valid time, correlating (307, 409), by the centralized controller, the first report message with the second report message according to the first user equipment identifier and the second user equipment identifier, and performing, by the centralized controller, event statistics collection related to the correlated first report message and second report message, wherein the determination whether the first user equipment identifier is consistent with a second user equipment identifier includes using a mapping rule that allows a mapping between different user equipment identifier types used in different systems, wherein, when the first user identifier is consistent with the second user identifier, the centralized controller indicates that the operation event is an operation event of the same user equipment.