Abstract: In recent years, there has been a tendency to increase the output power of radio frequency (RF) to meet the demands of long-distance communication. RF power amplifiers, serving as the final stage of communication systems, are highly susceptible to damage due to their high power output. Given that power amplifiers are relatively expensive and delicate components, it is crucial to focus on protecting them during the design phase to prevent issues such as overheating, over-temperature, over-voltage, and overloading, which can lead to amplifier failure or malfunction. Combining with the practical engineering applications of RF power amplifiers in ultra-short wave communication, this paper designs and constructs the detection circuit and protection circuit of a composite power amplifier system, and studies their operational capabilities, respectively. The designed detection and protection circuits enable real-time monitoring of signals with pulse widths ranging from 50 µs to 110 µs, corresponding to the duty cycle 4% to 30%, the circuit power response range −35 dBm to 0 dBm, and the switch insertion loss \le £2.6 dB. This circuitry has already been applied in the latest airborne equipment, demonstrating its positive impact on enhancing the reliability and lifespan of power amplifiers.