As an important means of jamming infrared guided missile, the jamming effects of the point source infrared decoy are related to many factors. It is very important for operation to study the motion characteristics of the infrared decoy after being dispensed. Through establishing the motion models of the point source infrared decoy, three kinds of dispensing modes such as upward, downward and lateral are simulated respectively. And the separation situation of the aircraft and the point source decoy at different viewing angle is obtained.