Abstract: In order to control the roof stability of fully mechanized mining face that is with deep dip angle and large mining height,we studied,through the research methods,such as the numerical simulation,theoretical analysis,engineering practice and so on,the overlying strata movement characteristics of the work face and mine pressure behavior,and also analyzed the relationship between work face’s support and?the movement of overlying strata,and then found out the reasonable control method to improve the roof stability.On this basis,and under the actual conditions of 509 working face on the No.3 coal mine,we put forward requirements for support to control the stability of roof,and took some actions to control roof stability,such as transformed the moving way of support,moved support in advance,added the regulator and the jack of regulator at bottom of support,and added metal net between the top beam and the roof.This research results can provide references and a good guiding significance to a mining with the same condition.