Abstract: SiO₂ filled hydrocarbon resin copper clad laminate was prepared by impregnation and vacuum hot pressing technology with polybutadiene as resin matrix, glass fiber cloth as reinforcement and SiO₂ as filler, and the effects of SiO₂ particle morphology (spherical shape and irregular shape) and particle size (2-20 μm) on the dielectric properties, bending strength, peeling strength and water absorption of copper clad laminates were studied. The results show that with the same particle size, compared with the irregular SiO₂ filled hydrocarbon resin copper clad laminate, the spherical SiO₂ filled hydrocarbon resin copper clad laminate had relatively low dielectric constant, dielectric loss and water absorption, relatively high bending strength and peeling strength, and relatively good comprehensive performance. With increasing particle size of SiO₂, the dielectric constant, dielectric loss, bending strength and water absorption of the spherical and irregular SiO₂ filled hydrocarbon resin copper clad laminate decreased, while the peeling strength increased.