As the length of horizontal well sections of regional governance drilling projects in coal mining areas increases， the problem of backing pressure during drilling becomes more and more serious， which directly affects the construction efficiency of drilling projects. Taking the Well Zhu 18 of a regional governance project in coal mining area as an example， this paper analyzes that the drop of the backing pressure is led by the friction resistance and rock cuttings bed caused by factors such as drilling trajectory， drilling tool assembly， drilling fluid performance， and displacement. In response to the above factors， corresponding measures have been taken to alleviate the backing pressure problem and the drilling efficiency of horizontal wells is improved.