A packet sending method, wherein the method comprises: receiving, by a network device, a packet; identifying, by the network device, that a flow to which the packet belongs is delay-sensitive traffic for a reserved resource, wherein the reserved resource comprises a quantity of packets that can be sent for the flow in one time window; and arranging, by the network device based on the quantity of packets that can be sent for the flow in one time window, and an accumulated quantity of packets that have been sent in the time window, and a quantity of packets already in a queue used to send the flow, the packet in a specific time window for sending; characterized in that the arranging, by the network device based on the quantity of packets that can be sent for the flow in one time window and an accumulated quantity of packets that have been sent in the time window, the packet in a specific time window for sending comprises: determining, by the network device, an arrival time window of the packet, wherein the arrival time window is a time window of the packet at an egress port of the network device when the packet arrives at the network device; querying, by the network device, for the quantity of packets in the current ingress queue; determining, by the network device, an ingress queue of the flow based on the arrival time window, the enqueue timing of the queue, the quantity of packets that can be sent for the flow in one time window, and the quantity of packets in the current ingress queue; adding, by the network device, the packet to the determined ingress queue of the flow; and opening, by the network device in a time window that is defined in the output timing and that is for opening a queue in which the packet is located, the queue in which the packet is located, and sending the packet. receiving, by a network device, a packet; identifying, by the network device, that a flow to which the packet belongs is delay-sensitive traffic for a reserved resource, wherein the reserved resource comprises a quantity of packets that can be sent for the flow in one time window; and arranging, by the network device based on the quantity of packets that can be sent for the flow in one time window, and an accumulated quantity of packets that have been sent in the time window, and a quantity of packets already in a queue used to send the flow, the packet in a specific time window for sending; characterized in that the arranging, by the network device based on the quantity of packets that can be sent for the flow in one time window and an accumulated quantity of packets that have been sent in the time window, the packet in a specific time window for sending comprises: determining, by the network device, an arrival time window of the packet, wherein the arrival time window is a time window of the packet at an egress port of the network device when the packet arrives at the network device; querying, by the network device, for the quantity of packets in the current ingress queue; determining, by the network device, an ingress queue of the flow based on the arrival time window, the enqueue timing of the queue, the quantity of packets that can be sent for the flow in one time window, and the quantity of packets in the current ingress queue; adding, by the network device, the packet to the determined ingress queue of the flow; and opening, by the network device in a time window that is defined in the output timing and that is for opening a queue in which the packet is located, the queue in which the packet is located, and sending the packet. determining, by the network device, an arrival time window of the packet, wherein the arrival time window is a time window of the packet at an egress port of the network device when the packet arrives at the network device; querying, by the network device, for the quantity of packets in the current ingress queue; determining, by the network device, an ingress queue of the flow based on the arrival time window, the enqueue timing of the queue, the quantity of packets that can be sent for the flow in one time window, and the quantity of packets in the current ingress queue; adding, by the network device, the packet to the determined ingress queue of the flow; and opening, by the network device in a time window that is defined in the output timing and that is for opening a queue in which the packet is located, the queue in which the packet is located, and sending the packet.