A method for maintaining a Network Address Translation (NAT) address mapping table, a Media Gateway (MG) and a Media Gateway Controller (MGC) are disclosed herein. The method for maintaining the NAT address mapping table includes: the MG creates a NAT address mapping table context as instructed by a MGC, where the NAT address mapping table context stores at least one NAT address mapping entry; and the MG operates the NAT address mapping table context to maintain the NAT address mapping entry stored in the NAT address mapping table context. Through the embodiments of the present invention, the NAT address mapping table can be maintained on the MG by operating the created NAT address mapping table context.