Abstract: In order to study the debris cloud characteristics of cylindrical projectiles impacting thin plate at hypervelocity, the process of cylindrical projectiles with different aspect ratios impacting thin plate with different attack angles were simulated based on the smooth particle hydrodynamics (SPH) method of numerical software AUTODYN-3D. The impact velocity of cylindrical projectile was set as 5 km/s and the aspect ratios of cylindrical projectiles were 0.5, 1.0, 2.0, and 4.0 respectively. The attack angles were 15° to 75°. The analysis of numerical simulation results indicates that most of the debris clouds formed by the oblique hypervelocity impact of cylindrical projectiles on thin plates are composed of small mass debris. The mass and kinetic energy of large debris are large, which is the main causes of damage to the rear wall. At the same time, when the aspect ratios of the projectiles are 0.5 and 1.0, the penetration ability of debris cloud at 15° attack angle is the weakest. When the aspect ratios of the projectiles are 2.0 and 4.0, the penetration ability of debris cloud at 75° attack angle is the weakest. The results may provide a reference for the optimization design of spacecraft protective structure.