The multi-payload collaborative reconnaissance has become a main operating mode of Unmanned Reconnaissance Aerial Vehicles(URAV) at present and for the future.According to the features of three airborne reconnaissance payloads:electronic reconnaissance device, SAR and tilted CCD camera with long focal length, the factors and indicators that have effect on multi-payload collaborative reconnaissance effectiveness were analyzed, and the model of the multi-payload collaborative reconnaissance effectiveness of UAV was established by using linear weighted algorithm.Finally, the reconnaissance effectiveness of an UAV with combination of any two devices of the three kinds of payloads was calculated out and analyzed under different intensity of electronic countermeasures (ECM) environment, and the availability of the model was proved.