This paper proposes a high-fidelity hardware-in-the-loop (HIL) simulation method for radar seeker verification in complex electromagnetic environments, achieving equivalent reconstruction of electromagnetic environments between microwave anechoic chambers and real-world outfield scenarios through collaborative modeling of outfield environmental signal computation and indoor radio frequency (RF) simulation. The model integrates an out-field environment signal reception power high-fidelity calculation module with an in-field radio frequency simulation module. Innovatively employing target scenario signal simulation and triad equivalent simulation techniques, it generates target echo signal parameter sets through multi-physics joint simulation. Combined with array coarse/fine control units and a high-dynamic-range power allocation algorithm, this approach thus overcomes the trade-off between large dynamic range and high spatial resolution inherent in traditional RF anechoic chamber near-field synthesis techniques. Experimental results demonstrate that this method significantly improves power field reconstruction accuracy under rain/snow/fog conditions, enables equivalent simulation of multi-equipment scenarios through loading outfield test data, and confines the deviation between seeker-received signal power and outfield measurements within required specifications, providing effective HIL simulation support for anti-jamming verification of new guided weapon systems.