Abstract: With the rapid development of underground engineering, the problem of surge water has become one of the main problems restricting the safety and operation of the project. In this study, through the self-developed visualized rough fissure negative pressure pumping and joint magnetic convergence device, we carried out the negative pressure pumping-grouting test of moving water fissure under the action of multi-factors, and investigated the spatio-temporal diffusion law of ordinary slurry and magnetic slurry under the action of magnetic field; Focusing on the analysis of the influence mechanism of different fissure inclination angle, negative pressure suction, dynamic water flow and magnetic field strength on slurry diffusion, a negative pressure suction-magnetic convergence dynamic water grouting model for inclined fissure under the consideration of magnetic field strength was established. The results show: ① Under the condition that other factors remain unchanged, compared with ordinary slurry, the maximum diffusion area of 90° fissure magnetic slurry under the magnetic field is enhanced by 49.02%, the maximum backwater diffusion distance is increased by 61.89%, and the maximum lateral diffusion distance is increased by 56.91%. It shows that the magnetic field effect can effectively enhance the slurry diffusion area. ② The slurry diffusion area grows 600.78cm2 at 0° inclination with a suction force of 80kPa, and the growth rate of diffusion area is 17.66%. It shows that the negative pressure suction force has an effect on the increase of slurry diffusion area. ③ The degree of influence on the slurry diffusion area is, in descending order of strength, fracture angle, dynamic water flow, negative pressure suction and magnetic field strength. ④ Verification analysis of the derived negative pressure suction-magnetic convergence dynamic water grouting model for inclined fissures shows that the maximum relative error with the actual is not more than 11.37%, which indicates that the established negative pressure suction-magnetic convergence dynamic water grouting model is able to describe the diffusion process of the slurry, and it can provide new research ideas and theoretical references for grouting and filling of water-excursion fissures under different inclination angles.