In order to analyze the stress distribution law and characteristics of the lower coal pillar after the upper coal seam mined in the short distance coal seam, the method of theoretical analysis was carried out. Firstly, through mechanical model analysis, the polar coordinate calculation formula of stress distribution of floor rock after mining was obtained. For the convenience of later analysis, the polar coordinate calculation formula was transformed and the stress distribution calculation formula in rectangular coordinate system was obtained. The calculation formula of stress was got, and the distribution curves of horizontal stress, vertical stress and shear stress of strata at different positions of the floor under the action of uniform load were drawn. From the trend of curve variation, it could be concluded that there were great differences in the concentration degree, propagation form and influence range of vertical stress, horizontal stress and shear stress in the coal pillar floor; the peak value of vertical stress appears in the middle of the coal pillar in the floor, and the stress decreases monotonously to both sides of the coal pillar, and gradually restores to the original rock stress value at the edge of the coal pillar floor, with the change of depth, the horizontal stress changed greatly, which was a peak value at the shallow position and two peaks at the deeper position. With the increase of depth, the peak value of horizontal stress gradually became less obvious, and finally tended to the original rock stress. The distribution law of shear stress at the deep and shallow parts of coal seam floor was similar, and shear stress at the same depth presented two peaks. The two peaks were evenly distributed on the symmetrical axis of the central position of the coal pillar.