Abstract: To meet the urgent requirement for a mobile and realistic target and jamming simulation method in the performance evaluation of new anti-stealth early warning radar under complex electromagnetic environments, a miniaturized P-band radar target echo and jamming signal simulator based on a UAV platform is designed. The miniaturization of the whole system is achieved by adopting a low-power RF front-end, FPGA baseband processing, and modular integration technologies. The total weight of the simulator is less than 6 kg and the power consumption is below 130 W, satisfying the payload constraints of typical rotor UAVs. The simulator can generate radar target echoes and multiple typical electronic countermeasure signals, including noise jamming, deception jamming, and dense false targets. When integrated with a UAV, it can dynamically construct complex electromagnetic environments in multi-dimensional geographic space. Field test results show that the developed system can effectively support the comprehensive evaluation of the early warning radar's detection performance, anti-jamming capability, and track quality under complex electromagnetic environments, providing a flexible and controllable new test method for the operational evaluation of early warning radar.