Shale gas survey wells are usually difficult to drill because of complex geological conditions. On the basis of shale gas survey and wellbore stability analysis of Chuanmudi 2 well, the organic silicon polymer drilling fluid system was selected, and through orthogonal test, the optimum dosage of main treatment agents, such as organosilicon modified polymer, multi-grade ultra-fine calcium carbonate, emulsified paraffin and silicon fluoropolymer, was determined, and the basic formula was formed. The system shows good drilling chips contamination resistance, calcium invasion resistance, etc. in the laboratory test evaluation. Inhibitory and plugging properties. Field application shows that after using organosilicon polymer drilling fluid system, complex conditions in well Chuanmudi 2 have been significantly improved, well safety has been effectively guaranteed, and well has been successfully drilled to the designed well depth, realizing geological objectives, and drilling efficiency has been greatly improved compared with the same type of drilling in the same area. The research results can provide reference for selection and application of drilling fluids in complex formation of shale gas survey wells.