Abstract: In order to prolong the service life of a mine, we use gangue paste filling mechanized mining to protect coal pillar. The method of theoretical derivation and physical simulation experiment was combined to study the roof control of gangue paste filling. Analysis results show that the maximum control distance is 9.9 m at the first test surface mining, coal feed step for 700 mm, mining three knife for a filling, using split type hydraulic support to control roof; when working face excavated to 160 m, we measured the paste filling mining surface subsidence coefficient of 211.2 mm, the subsidence coefficient 0.08 is far less than provisions of the surface subsidence coefficient of 0.15, the first test surface mining theory of paste filling process parameters design can meet the needs to protect the surface buildings; the technology is feasible.