When the temperature changes or is not uniform,the structural and optical elements of airborne photoelectrical equipment would deform,which may have effect on the optical system performance.In addition,too high or too low temperature may decrease the reliability and life of the critical elements.Therefore,it is very important to carry out thermal simulation and evaluation in design of the airborne photoelectrical equipment.The detector and PCBs are the main hot elements of the airborne photoelectrical equipment.So,how to improve the precision of thermal simulation becomes the key point to improve the validation of evaluation.In this paper,the composition,working principle,normal thermal modeling method of detector and PCB are presented,and an improved modeling method of the thermal simulation is given.Experimental verification results show that the precision of the proposed thermal simulation is improved remarkably,and thus the validation of evaluation is improved.