In order to study the motion characteristics of a certain type of rotary selfstabilizing terminal sensitive submunition, the submunition′s asymmetric structure characteristics and its initial projection condition were fully considered. The dynamic unbalance missile model was introduced to derive the 6 degrees of freedom trajectory equation of the submunition and analyze the characteristics of steady state scanning motion of submunition. Results show that the submunition′s asymmetric mass distribution and the initial angular velocity are the necessary condition for the realization of the steady state scanning. The scanning frequency of the submunition is only determined by the projection angular velocity ω_σ0, and is positively correlated with the ω_σ0. When the initial pitch angle φ_a0≥0°, the overall trend of scanning angle is increased, and when φ_a0＜0°, the scanning angle decreases and then increases. The scanning area is positively correlated with the mass ratio of weight and projectile, the φ_a0, the initial yaw angle and the ω_σ0, and is negatively correlated with the ratio moment of inertia of the center cylinder.