To address the lack of repeatable full-life degradation data and the limited capability of conventional simulation and calibration for infrared seeker servo systems under coupled opto-mechanical-electrical-computational effects, a hardware-in-the-loop simulation and verification platform based on physical isomorphism mapping is developed. The platform reconstructs the sensing–control–actuation closed-loop signal chain and enables millisecond-level synchronized acquisition and unified packaging of multi-domain parameters. A hybrid diagnostic scheme is implemented by combining GMM-based continuous health scoring with HSMM-based degradation-stage recognition, together with residual-constrained remaining useful life (RUL) prediction. Accelerated aging tests with graded fault injection reproduce eight evolving fault patterns; the overall prediction accuracy reaches 90.45%, with relative errors stably within 15%. The platform provides a high-confidence testbed for condition-based maintenance and life-cycle management of electro-optical equipment.