Reasonable size of coal pillar was the guarantee key factors to the stability of roadway. Under the engine background of shallow buried depth medium-thick seam, based on Shangwan Mine 1-2上  coal seam roadway settlement, theoretical calculation and numerical simulation were applied, 303 fully mechanized working face coal pillar between belt transport lane and auxiliary transport lane mine pressure and stress distribution characteristics were studied, The reasonable size of coal pillar was settled. The result showed that the design of coal pillar was 15 m, the central pillar abutment pressure peak superposition, with damage in coal pillar; When designed 20 m, 25 m, on both sides of the coal pillar abutment pressure formed the obvious saddle distribution. Considering the stability of coal pillar and extraction efficiency, the coal pillar width was designed to 20 m.