Abstract: In view of the practical problem that the geometric parameters of standard specimens differ from those of actual engineering components, and their impact responses are difficult to directly reflect the influence of planar dimension changes on structural performance, this paper analyzes the influence law of planar dimensions on the low-speed impact characteristics of composite laminated plates through experimental and simulation methods. Based on the three-dimensional Hashin criterion and bilinear constitutive criterion, a finite element model was established. The low-speed impact response characteristics and damage states of composite laminated plates under standard samples were analyzed. Corresponding low-speed impact tests were carried out and the simulation analysis was verified. Based on the simulation model, the influence law of planar dimensions on the impact response and damage conditions of composite laminated plates was studied. Research results show that: The planar dimensions have a significant impact on impact resistance performance and damage morphology. As the planar dimensions of square and rectangular laminates increase, the peak load and absorbed energy show a downward trend, while the maximum central displacement shows an upward trend. In terms of damage conditions, the damage area presents a decreasing trend, and the damage area is concentrated towards the impact region with weakened edge damage. When studying the size effect of aspect ratio, within a certain range of increasing aspect ratio, the response law and damage trend are consistent with those of square and rectangular planar laminates; the larger the aspect ratio, the more concentrated the damage distribution towards the central axis region of the impact.