After deducing external trajectory calculation method under non-standard atmospheric conditions for 37 mm anti-aircraft gun, which was widely used in the field of weather modification, the ballistic data in uniform cross wind and range wind field were simulated. The results show that the wind made a great influence on the flight path of projectile. The range wind can change the ballistic range by affecting the size and direction of air resistance. The cross wind can generate a lateral deviation of the trajectory along the wind by affecting the direction of the air resistance. On the same launch elevation angle, with the change of wind speed, the trajectory deviation correction caused by cross wind and the range correction caused by range wind showed a variation law that was similar to arithmetic progression. Through fitting analysis, the relationship among wind speed, elevation and trajectory correction was obtained，which can be used to estimate trajectory correction under arbitrary wind speed in actual operation.