The special project of comprehensive geophysical research drilling in the Xiaoqinling national integrated exploration area aims to find out the deep geological structure and reservoir characteristics of the hidden ore bodies in the Xiaoqinling area. Due to lack of deep hole and deep geological data， many unknown factors exist in construction. Considering the basic condition of this special drilling project， strata lithology， drilling depth and final hole diameter， practical drilling equipments and wire-line core drilling and LBM drilling fluid system as the main drilling technology should be selected to meet the construction needs. During the drilling process， technical problems such as low core recovery rate in upper strata， water gushing， adhesion stuck， falling block stuck， leakage in the hole， anti-slope in slate layer and difficult in lifting casing were encountered. Relevant feasible solutions were made to provide certain reference for the drilling construction in this mining area or similar strata in the future. At the same time， a mud system for fractured and poorly consolidated strata was summarized and formed， which has achieved good results in maintaining the well wall， effectively preventing major accidents in deep holes， improving drilling efficiency and saving drilling costs.