In order to systematically investigate the angle-of-attack coefficient of mortar projectiles and provide a reference for analysis on ballistic blasting of the fuze in mortar projectiles, aerodynamic characteristics of mortar projectiles at different angle-of-attack and Mach number were simulated by FLUENT, and Matlab was used to fit results of numerical simulation. Change rule and the range of angle-of-attack coefficient of mortar projectiles in varied forms were given. The results indicate that the angle-of-attack coefficient of mortar projectiles is a function of Mach number in subsonic, ranging small with variety of mach numbers. The angle-of-attack coefficients are different in diameter and shape of mortar projectiles, ranging from 18.2 to 29.1 for the diameter from 60 mm to 100 mm.