For because of the weak rock roadway, in the process of mining face in the process of the extraction and produce stress concentration, the phenomenon is common problem of floor heave of roadway, the plastic zone theory, USES the roadway, butterfly in sun Tuan ore extraction roadway floor heave damage as the research background, used FLAC^3D numerical simulation software analysis of floor heave of roadway under the influence of mining mechanism.The results show that: ① roadway stress environment is different, the formation of plastic zone shape will be different, large principal stress ratio, the plastic zone of roadway surrounding rock will appear butterfly distribution, and the direction of butterfly leaf rotation with the direction of principal stress rotation; ② under the influence of mining, the surrounding rock of mining roadway will produce a large deviating stress, and the direction of the maximum principal stress will deflect to one side of the mining face, so that the butterfly blade in the plastic zone will turn to the roadway floor. The butterfly blade’s rotation will cause the floor rock to be destroyed, resulting in floor heave.The research results provide a new understanding of the failure mechanism of roadway floor heave.