The preliminary selection of supporting parameters and equipment model of coal mining face and mining roadway often rely on engineering experience under similar conditions. However, for the first mining face of a new mining area, there was insufficient practical data and experience data for reference. Against to this problem, the relationship between vertical ground stress and horizontal ground stress was discussed firstly. The plane strain mechanical model of coal seam mining was established. The theoretical solution to the stress change of the top and bottom floor after mining was made, and the stress concentration coefficient increased of the leading support with mining thickness and width was revealed., but the rate of increase gradually slowed down. The floor disturbance stress propagated to the deep rock mass in the form of elliptical contours. The front floor was easy to cause compression shear failure due to stress concentration, and the floor of the goaf was easy to cause tensile damage due to pressure relief expansion. Through the research of the paper, it can provide preliminary theoretical guidance for the design of supporting parameters and equipment model for the first mining face.