Aiming at requirement of artillery trajectory data calculation accuracy inspection, the nonstandard firing condition trajectory data calculation accuracy inspection method based on orthogonal test design is designed. Analyze the current research situation at home and abroad, use orthogonal test design to ascertain multi-factor, multi-level simulation firing conditions. Based on firing table and single modification vector accuracy inspection method to carry out research on accuracy inspection method of nonstandard firing condition, then verify it in new project. The results show that the method can realize automatic test and inspection for trajectory data calculation accuracy inspection, and make statistics and analysis for the trajectory data calculation accuracy.