In-situ detection is an important means to ensure the readiness of airborne EW equipment, the current in-situ detection mode mainly carries out rough detection of functions, with incomplete detection coverage and incomplete troubleshooting of potential failure, which makes it difficult to find the degradation of equipment operational performance in time. Aiming at these shortcomings, the concept of in-situ depth detection of airborne EW equipment is proposed, and its connotation, mode and key technology are studied. Engineering practice is carried out in the in-situ fault depth diagnosis, equipment performance change trend monitoring and rapid positioning calibration of airborne EW equipment, which can keep the readiness rate of pilot equipment above 95%, The results show that the in-situ depth detection technology of airborne EW equipment plays an active role in improving the readiness rate of equipment.