The invention discloses an output access control method and an output access control device, wherein, the output access control method comprises a three-layer input port used for receiving data message; the three-layer input port controls whether to transmit the data message to a three-layer output port which is matched with the destination IP address of the data message according to a preset access control list; the output access control device, which is arranged at the three-layer input port of a switchboard, comprises a receiving module used for receiving the data message, a transmit control module used for controlling whether to transmit the data message to the three-layer output port which is matched with the destination IP address of the data message according to the preset access control list. The method and the device realize the output access control of the data message by arranging an ACL at the three-layer input port of the switchboard which does not support the ACL.