To deeply understand the nature of trajectory correction mechanics of fixed canard dual-spin projectile, the angular motion characteristics and control stability under the control of fixed canard were studied. According to the knowledge of exterior ballistics of rocket and projectile, the complex attack angle motion equation of the fixed canard dual-spin projectile is established, the expressions of the specific solution corresponding to the control force term of canard surface and general solution corresponding to the resulting initial disturbance term are derived. It is theoretically explained that after the fixed canard takes control, the complex attack angle motion of a dual-spin projectile is composed of the forced angular motion of the complex dynamic equilibrium attack angle with the complex control equilibrium attack angle, and the free attack angle motion generated by the initial disturbance of the canard control. Based on this, the control stability condition of the fixed canard dual-spin projectile is proposed, and the mechanical nature of the trajectory correction of the fixed canard dual-spin projectile is analyzed by solving the complex velocity deflection angle caused by the control force of the canard surface and the complex disturbance attack angle. The numerical calculation results of the trajectory that the fixed canard is controlled at different roll angles show that the angular motion’s analytical solution deduced theoretically is consistent with the numerical calculation results in terms of frequency and amplitude. It’s verified that the complex attack angle motion equation under the control of fixed canard deduced in this paper and its analytical solution and the control stability condition are reasonable and feasible, which provides a theoretical basis and design reference for the development of this type of projectile.