To improve the precision of the projectile fired，one-dimension trajectory correction devices depending on controlling the damper to open variable areas to change damp-increasing affection was proposed，and changes of drag coefficient accompanied by angle-of-attack and wind speed under different open areas were analyzed． Mathematical model was built between increased drag coefficients and variable areas opened by the damper． Furthermore，mathematical expressions of increased drag coefficient in repeated remediation were also deduced． Tak ing a certain type of projectiles as an application background，influences of flying distance caused by opening variable area and realizing mul tiple range corrections were researched with the theory of numerical analysis and simulation experiments．