Abstract: Based on such characteristics as high porosity, high permeability, loose formation and thick crude reservoir in block Gao104-5 in Jidong oilfield, a totally new temporary shielding plugging drilling fluid system of general applications, KCl-BPS polymer drilling fluid is developed. In this system, the black organic positive colloid (cationic asphalt) is used as the main additive for reservoir protection, and various temporary shielding plugging materials are selected according to the new principle, potassium chloride and certain kinds of polymers are also added into. Laboratory study and field testing shows that the system possesses such advantages as better cuttings transportation, better shale inhibition, good lubricity and sloughing control, etc. The drilling fluid performances are easy of conditioning and regulating, and minimal formation damages are produced by using this drilling fluid system.