An acknowledgment packet sending method and device are provided, so as to reduce sending of acknowledgment packets on an air interface, and improve efficiency of air interface resource utilization. After receiving a TCP acknowledgment packet that is sent by a TCP protocol entity unit of a communications device and does not carry data information, an RLC protocol entity unit of the communications device discards the received TCP acknowledgment packet; or determines, according to a sending status of an RLC acknowledgment packet, whether to send a TCP acknowledgment packet to a peer communications device, and performs corresponding processing according to a result of the determining.