A packet processing method in a hybrid access network, wherein the hybrid access network comprises a first network device and a second network device, a first tunnel and a second tunnel are established between the first network device and the second network device, the first network device comprises a first cache and a second cache, the first cache is configured to store a first sending window, the second cache is configured to store a second sending window, and the method characterized by: sending, by the first network device, a first data packet in the first sending window to the second network device by using the first tunnel, wherein the first data packet carries a first sub-link number, and the first sub-link number represents a sequence number of the first data packet in the first tunnel; in response to receiving a first acknowledgement response sent by the second network device, increasing, by the first network device, a size of the first sending window based on a first proportion, wherein the first acknowledgement response carries a first acknowledgement number, the first acknowledgement number is obtained based on the first sub-link number; in response to not receiving, within a first predetermined time, the first acknowledgement response sent by the second network device, decreasing, by the first network device, the size of the first sending window based on a second proportion, wherein the second proportion is greater than the first proportion; receiving, by the first network device, a second data packet, wherein a next hop through which the second data packet passes to arrive at a destination address is the second network device; and in response to determining that the size of the first sending window is greater than or equal to a first threshold, storing, by the first network device, the second data packet into the second cache, so that the second data packet enters the second sending window; and sending, by the first network device, the second data packet to the second network device by using the second tunnel. sending, by the first network device, a first data packet in the first sending window to the second network device by using the first tunnel, wherein the first data packet carries a first sub-link number, and the first sub-link number represents a sequence number of the first data packet in the first tunnel; in response to receiving a first acknowledgement response sent by the second network device, increasing, by the first network device, a size of the first sending window based on a first proportion, wherein the first acknowledgement response carries a first acknowledgement number, the first acknowledgement number is obtained based on the first sub-link number; in response to not receiving, within a first predetermined time, the first acknowledgement response sent by the second network device, decreasing, by the first network device, the size of the first sending window based on a second proportion, wherein the second proportion is greater than the first proportion; receiving, by the first network device, a second data packet, wherein a next hop through which the second data packet passes to arrive at a destination address is the second network device; and in response to determining that the size of the first sending window is greater than or equal to a first threshold, storing, by the first network device, the second data packet into the second cache, so that the second data packet enters the second sending window; and sending, by the first network device, the second data packet to the second network device by using the second tunnel.