Abstract: A probability analysis method for multiple impacts to protect against high-speed projectiles without excessively increasing the areal density of the protective structures was proposed in this paper. Assuming a random distribution of multiple projectiles and neglecting low-probability events, the number of impacts that require protection was identified. Building on the foundation of effective single-impact protection, a method of areal density compensation was presented. A two-stage light gas gun test verification was conducted on 100 cylindrical aluminum alloy projectiles sequentially impacting a square composite target plate with a side length of 2000 mm. The results show that protection againt dual-impact was sufficient for this scenario. An additional layer of aramid/boron carbide ceramic (B₄C)/UHMWPE plate with an areal density of 25 kg/m² was incorporated into the existing protective structure which consists of two layers of aluminum alloy plates and UHMWPE plates with a combined areal density of 37.5 kg/m². The enhanced protective structure was effective in withstanding sequential impacts at velocities of 1.8 km/s and 1.9 km/s. The approach provides an important reference for designing protective structures against multiple impacts.