Abstract: Due to the large section size and high stress level in the deep chamber,it is more difficult to control the surrounding rock of the chamber. This paper studied the expansion law and influence mechanism of different grouting fluid in the surrounding rock cracks of the deep large-section chamber by measuring deformation failure characteristics and analyzing instability causes of surrounding rock of main drainage pumping-room chamber in Shunhe Coal Mine -702 m horizontal. The reinforcement scheme of " high strength grouting cable+wall grouting" for deep large-section chamber was put forward,and the field industrial test was carried out. The results showed that surrounding rock loose circle in deep large-section chamber was irregular,the loose range was large,the surrounding rock broken degree was high near the gateway:two-side loose range was the largest,the roof second,the floor was small,and rock breaking difference were large in different locations. The causes of surrounding rock instability in large-section chamber were high stress level,low surrounding rock strength,fissure water immersion,poor support structure and no support in floor,and fracture propagation penetration was the main control factor of surrounding rock instability. The influence of grouting pressure on slurry diffusion in surrounding rock cracks was greater than that of water-cement ratio. The larger the water-cement ratio and grouting pressure was,the larger the slurry diffusion radius was,and the tangential expansion range of slurry was larger than that of radial. The optimal water-cement ratio and grouting pressure were 0. 7 and 1. 5 MPa respectively. The high-strength grouting cable achieved uniform anchoring bearing in axial and circumferential. After the reinforcement scheme of " high-strength grouting cable + wall grouting" was carried out,the maximum roof subsidence was 8 mm and the maximum two-side convergence was 24 mm,and the surrounding rock control effect was remarkable.