Abstract: Aiming at the difficulties of drilling the complex formation with supersition of fault breccia and coal seam during exploration in Zhenlong mine, the characteristics and complexity of the formation were comprehensive analyzed, and potassium polyacrylate drilling fluid was used to protect the hole wall. Through the exploration of using the potassium polyacrylate drilling fluid in two boreholes, it indicated that the potassium polyacrylate drilling fluid had good performance, moderate viscosity, reasonable filtration, and it could form a thin and dense mud cake, and has strong adaptability. This drilling fluid plays a good role in preventing the hole wall from shrinkage and collapse, and it can reduce the hole accident rate and improve the drilling efficiency.