Abstract: The fidelity of laser target simulator is mainly used to evaluate the degree of approximation between the target simulator's output laser and the laser irradiator's output laser during its transmission and being reflected by the target surface in actual battlefield. The effectiveness of fidelity depends on the applicability and actual operability of the evaluation scheme. An effective evaluation scheme for studying the fidelity of the laser target simulator was proposed, and the quantized fidelity of every specific indicator was also defined. Firstly, the laser energy transport model of target laser in real battlefield and the control model of light spot in the hardware-in-the-loop simulator were calculated. Then, according to the two models, the fidelity evaluation content of the characteristic of laser pulse and laser spot in the laser target simulator was studied with emphasis. And finally, by calculating the weight of the specific index, the whole fidelity of laser target simulator was obtained. The fidelity evaluation scheme can be applied to the design and performance evaluation of the laser target simulator, so it can reduce the cost and time by doing the test of the laser target simulation in the hardware-in-the-loop simulation system, which means a lot in designing modern weapon system.