Abstract: Roadside support is a key factor in determining the success of gob-side entry retaining. The support system consists of the roof-roadside support body-floor. Therefore,it is particularly important to study the deformation and failure characteristics of the roof and floor of the surrounding rock affected by the roadside support structure. Taking Zhujiadian Coal Mine as the geological background,this paper studies the deformation and failure characteristics of the surrounding rock under different elastic modulus of the concrete pillars of the roadside support structure through ANSYS numerical simulation software. The results show that. When the concrete pillars are under low elastic modulus,with the increase of elastic modulus,the deformation amount decreases and the roof subsidence is reduced simultaneously. When designing the concrete pillars,the yield deformation capacity should be considered. Excessive stiffness will lead to obvious brittle failure of pillars.