This application provides a buffer allocation method and a device. The method includes determining, by a device, a first output rate of a first queue on the device and a second output rate of a second queue on the device. The method also includes separately allocating, by the device, a first buffer to the first queue and a second buffer to the second queue based on a ratio of the first output rate to the second output rate. The device separately allocates a buffer to each of queues based on a ratio of output rates of the queues, so that a ratio of output traffic of the queues meets an expected scheduling ratio.