Abstract: In view of problem that there is a big difference between calculated load and real load when roof load is estimated or thin plate theory model is used to study mechanical characteristics of advanced support at present, a new type of roadway advanced support was designed, and the mechanical characteristics of the advanced support were studied according to spatial effect of roadway excavation. Based on spatial effect, the coupling mechanism between advanced support and surrounding rock of roadway was studied, and coupled mechanical model of the advanced support and surrounding rock was built. The research results show that along the direction of roadway excavation, the roof load borne by the roadway advanced support decreases gradually, the closer to the working face, the greater the roof load is, and the front end strength of the advanced support is higher than that of the back end. The support timing of the advanced support is very important for the stability of roadway roof, the closer the advanced support is arranged to the roof of working face, the smaller deformation of the roadway roof will be; while the larger the load borne by the advanced support is, the higher the strength required will be.