The invention relates to L-band RF (Radio Frequency) system output port protection equipment which comprises an L-band RF system output port protection circuit arranged in a metal sealed cavity, wherein the circuit comprises a coupler, a detection comparison circuit and a digital control feedback circuit; the detection comparison circuit comprises a forward detection circuit, a reverse detection circuit, a tuning circuit and a comparator; the data feedback circuit comprises a data processing circuit, a VSWR (Voltage Standing Wave Ratio) indication circuit and a protection judgment circuit; after the equipment is connected with an RF system final amplifier, an L-band incident wave is separated from a reflected wave in proportion by utilizing the coupler, the separated reflection quantity and incidence quantity are compared by the detection comparison circuit, then a logic level is output, and connected with the digital control feedback circuit, and port matching is judged by data processing, so that when a port is mismatched, the protection circuit can timely close a corresponding sending signal, and a protection function is exerted; and the whole equipment has the characteristics that the equipment is small, exquisite, light, and sensitive in indication and judgment.