Abstract: According to high difficult contral problems of surrounding rock during a fully- mechanized mining process of thin seam with soft roof and floor, a surroun ding rock deformation mechanics model of the thin seam with soft roof and floor was established. In combination with actual conditions of the site, FLAC3 Dnumerical si mulation was applied to analyze a surrounding rock plastic zone, surrounding rock vertical stress and support pressure variation law in front of the coal wall during the mining process of the thin seam with the soft roof and floor. A surrounding rock failure mechanism during the fully- mechanized mining process of the thin seam was obt ained. The site measured mine pressure results of No. 1705 E Coal Mining Face in Zhaoguan Mine showed that an initial falling distance of the immediate roof was18.2 m, the initial falling distance of the main roof was 37. 8 m and the periodical roof pressure distance was 16. 0 m in average. The support pressure of the coal wall was 0 bviously increased with a distance of 13 m in front of the coal wall and the influence scope was 0 ~ 25 m. The max convergence between the two sidewalls of the gatew ay was 300 mm. The max deformation of the roof and floor in the gateway was 900 and 500 mm individually. The site measured data of the surrounding rock deformatio n could be fitted with the numerical simulation.