The invention provides a base station and an automatic retransmission scheduling method thereof. The automatic retransmission scheduling method includes the following steps: when at least one first layer of protocol data unit of a first protocol layer constitutes a second layer PDU of a second protocol layer, assigning a retransmission serial number of the second layer PDU according to a serial number of the first layer PDU; sending the second layer PDU to a user equipment; receiving a status report of a first retransmission mechanism of the first protocol layer, and an acknowledgement serial number indicates that receiving of multiple PDUs of the first protocol layer by the UE is acknowledged; comparing the retransmission serial number of the second layer PDU with the ACK serial number, and determining whether to disable retransmission of the second layer PDU based on a second retransmission mechanism.