Rockburst is a common dynamic disaster in underground engineering under high ground stress. A large number of rockburst examples show that there is a strong correlation between the instability failure of slab cracking surrounding rock and rockburst during the excavation process of hard and brittle surrounding rock. Seven cracks were made in a 150 mm × 150 mm × 35 mm granite cube sample, the lengths of cracks were reduced from the free face to the inside according to a certain proportion. The granite is cut to form a slab-like structure with the same thickness, and the slap cracking sample model was made. The uniaxial compression test was carried out on the cracking samples. Combined with the numerical simulation results, the crack initiation, propagation characteristics and failure process of the cracked rock samples were analyzed, and the relationship between the instability of the slab cracking surrounding rock and rockburst was revealed. The results show that the cracking of surrounding rock plate is easy to induce sudden rockburst disaster, but it also provides the possibility for monitoring and early warning of rockburst disaster. With the increase of the distance between surrounding rock and the excavation face, the failure mode of slab crack structure becomes complex and the degree of failure increases gradually. It is found that there are three types of failure mechanism in the process of slab rockburst formation. The rock slab on the sample that is a certain distance from the excavation frontage is the first to rupture. The failure of the rock slab far away from the excavation free face is relatively rapid, and its fracture mechanism is more complex, with the largest degree of damage, resulting in a large number of rock blocks and cuttings. The slabs close to the excavation face are mainly bent and broken, forming large blocks or slab-like blocks. Once the rock slab is bent and broken at the face of excavation, the slab-like rock block formed at the face of excavation and the inside of surrounding rock will pop out at a high speed instantly, resulting in a rockburst disaster. The results reveal the process of rockburst of slab cracking hard rock structure under high stress condition, which can provide a scientific basis for the prevention and control of rockburst.