Abstract: In order to study the influence of jointing degree and joint inclination angle on the fragmentation characteristics of rock mass, sieving was carried out on the fragmentation particle of different jointed specimen under uniaxial compression. Different size particles were classified into four groups including coarse, medium, small and fine particle. Fragmentation distribution law of the specimens was analyzed along with the change of joint inclination angle under the same jointing space and different jointing degree conditions by calculating the particle mass percentage, particle size, specific surface area and fractal dimension of the fragment. The results show that the degree of breakage of the specimen decreases first and then increases with the increase of the inclination angle, and the degree of fragmentation is the lowest when β=45°, and the degree of fragmentation is high at β=0°, 30° and 90°. When the center distance of the joint center is 30 mm, the joint connection rate is smaller, the more serious crushing. When the joint connection rate is 0.8, the greater the center distance of the joint, the more serious the fragmentation.