IR imaging simulation technology of space target is of great significance in military and national defense,space exploration and other fields. In this paper,a method based on improved Delaunay triangulation for IR radiation imaging of space target is presented. Firstly,the temperature of each node is calculated by node network according to the heat balance equation. Secondly,the STK is used to get the positional relationship of the detector,the target,the earth and the sun. Then IR radiation intensity of the target is obtained from the node temperature. Finally,the improved Delaunay triangulation method is put forward to reconstruct the target to obtain IR images. In this paper,an imaging simulation experiment is carried out as an example. The experimental results verify the effectiveness and efficiency of the imaging method,which is of great value for IR detection and recognition of space target.