Abstract: The cone pinhole that is a new structure pinhole is used for spatial filtering in high solid-state laser system. Its smooth inner surface will reflect the unwanted light to prevent plasma closure that easily happens in high energy running. The comparison between the cone pinhole and the washer pinhole shows that the cone one performs better under high energy running. The cone pinhole can avoid the plasma closure effect more efficiently. Combined with the adaptive optical technology, it ensures that the beam path is unobstructed. The use of seven-order cone pinholes in spatial filters makes the high energy output more stable, and the output energy reaches 7988 J, which means the single beam power density reaches 6.2 J/cm2. The method for designing the cone pinhole is also presented.