Abstract: In order to study the instability and rupture evolution characteristics and fissure development laws of coal body under the action of surrounding rock pressure after water jet groove digging and hole forming, and to verify the fissure development effect after jet coal breaking, GDEM-blockDyna numerical simulation software is adopted to simulate and analyze the coal body rupture characteristics and the basic characteristics of fissure development around the hole. A similar material model compression experiment is carried out based on the pressure rupture experimental system, and joint monitoring is conducted through the full field strain and acoustic emission system, the failure state and damage law of coal bodies around the hole under the load bearing situation are explored. The research results indicate that the coal bodies around the water jet hole will further produce damage cracks under the action of surrounding rock stress, mostly radial fissures, and the failure mode is mostly tensile failure; There is a positive correlation between the quality of groove digging and hole forming and the coal body fissure development effect, coal bodies with high quality of jet groove digging and hole forming are more likely to develop multiple strips of fissures in their internal structure; Under the action of confining pressure, the degree of fissure development and expansion around the hole is significantly improved, multiple strips of fissure channels are formed and the permeability of coal seams is significantly improved.