In order to quantitatively analyze the development of overburden fractures in the roadway along the headway for pressure relief at the cutting top, so as to determine the reasonable height of the cutting top, a quantitative statistical analysis method based on Avizo software was proposed. Based on the engineering background of 8104 return air roadway retaining along the headway in Nianyan Coal Mine, theoretical analysis, numerical simulation and field industrial tests are used to study the overlying rock migration law and fracture development of the retaining under the condition of no cutting and different cutting height based on Avizo software, The mining pressure development law and its effect of cutting roof relief along the headway retaining are also analyzed, The results show that: (1) The height of caving zone increases with the height of cutting top, and the height of fracture zone is the same as that without cutting top.(2) Under the condition of roof cutting, roof fissure area and gob gangue compacting void area decrease exponentially with the increase of roof cutting height. When the top cutting height is 12 m, the top cutting effect is the best. Compared with no roof cutting, roof fissure area and gob gangue compacting void area decrease by 74.3% and 38.4%, respectively. (3) The displacement of top and floor and the displacement of two sides along the goaf retaining roadway show three significant characteristics: slow deformation, rapid deformation and deformation tends to be stable. The displacement of top and floor and the displacement of two sides stabilize within 400 mm after the delayed working face is 300 m, which ensures the safe and efficient production of the mine.