For the purpose of achieving high-quality athermal imaging in the infrared detection system, an antireflection coating in the wave band of 3.7-4.8 μm was prepared on aspheric chalcogenide glass substrate. Adhesive layer material was selected in the experiment to improve the adhesion between the substrate and the coating. The finite element method and multi-physics simulation software were used to build a three-dimensional model that combined temperature field and thermal stress field. The stress distribution of aspheric film was analyzed. In view of the simulation results, the deposition process was optimized. The thermal stress of the chalcogenide glass substrate was reduced by temperature gradient heating and the stress of the deposited film was released by in-situ vacuum annealing so as to solve the film stripping problem of the aspheric mirror. The prepared film passed the tests of adhesion, humidity, and moderate friction of the MIL-C-48497A standard and the average transmittance in the wave band of 3.7-4.8 μm was 99.12%, which means the prepared film met the index requirements of infrared detection system.