Abstract: In order to study the effect of in-situ stress on the pressure and permeability of coal reservoir in the Northeast of Pingding Shan mining area , the method of obtaining in-situ stress by hydraulic fracturing is adopted based on the test data of hydraulic fracturing and well test engineering in coal-bed methane wells, the characteristics of in-situ stress development in the northern mining area of Pingdingshan are studied, and the influence of in-situ stress on the pressure and permeability of coal reservoir is analyzed. The study shows that the present in-situ stress field is mainly horizontal stress and belongs to the typical type of tectonic stress field, and the overall stress field is characterized by high dip fault or fracture development; the maximum horizontal principal stress, minimum horizontal principal stress, lateral pressure coefficient and lateral pressure ratio increase linearly with the increase of buried depth.Buried depth is about 682 m geostress type conversion, the geostress type in the vertical transformation is mainly caused by the Pingdingshan mining area multi-stage tectonic movement of the results of stress superposition；The pressure of coal reservoir increases with the increase of minimum horizontal principal stress ，d vertical stress, effective principal stress and principal stress difference. The permeability of coal reservoir decreases with principal stress difference, maximum horizontal effective principal stress and minimum horizontal effective principal stress in negative exponential form.It is the key layout area for coal bed gas fracturing and other reservoir reconstruction and underground coal seam permeability increasing and pressure relief engineering.