A microwave transmission apparatus is provided. A multiplexing unit generates multiplexed data based on a service clock rate. An interface unit writes and reads the multiplexed data at the service clock rate and a read clock rate respectively. An encoding and mapping unit performs encoding and mapping on the multiplexed data using a symbol clock rate to generate symbol data, and sends the symbol data to up conversion units. A clock tracking unit generates the symbol clock according to the system clock, and performs frequency division on the symbol clock to acquire the read clock. A stream control unit adjusts the service clock rate according to a water line error generated by the interface unit, so that the service clock rate is equal to the read clock rate. As a frequency and a phase of the system clock are fixed, even ACM switching occurs, the system clock is stably transferred.