Abstract:the effect of open-field backfilling mining method on surrounding rock and surface is studied by using orthogonal test design method. The stress and strain laws of surrounding rock and surface are studied when different sizes of ore house and pillar and different settlement rates of backfill. The results show that; The value of roof tensile stress is not only related to stope span,but also closely related to pillar size, roof connection of backfill and settlement rate.From the overall displacement, it can be seen that, with different calculation schemes, subsidence deformation will occur on the surface more or less, and the maximum displacement occurs on the upper part of ore body excavation. In the same calculation scheme, there is a relationship between the displacement at different positions: Room displacement > pillar > displacement > surface displacement.At the position of the upper and lower wall faults, there are obvious displacement barriers. With the same size of ore house, the displacement decreases with the increase of pillar size. When the room size is larger than a certain value, the mining of ore body will have an impact on the surface, and there are certain safety risks.