The invention discloses an xDSL wire card energy saving method and device. The method comprises the steps that according to the state of each user port on an xDSL wire card in an office end device, non-active user ports are determined; and the non-active user ports on the xDSL wire card and related non-active devices are controlled to state a power consumption prevention state. According to the related non-active devices, all user ports of the related devices are non-active user ports. The device comprises a user port state determination module and an energy saving processing module. According to the invention, the device automatically determines the state of each user port, controls the user ports which meet conditions and carries out the operation of energy saving of the related devices through software; the speed is fast; other auxiliary devices are not needed; the efficiency of xDSL wire card energy consumption reducing is high; and a lot of energy can be effectively saved.