The high content of clay in Bohai Oilfield reservoir and the serious mud-making in drilling process make it difficult to control the rheology of drilling fluid.The amidocyanogen silicone inhibitor is optimized through laboratory experiments, and the mechanisms of amidocyanogen silicone and effect on JFC drilling fluid principle are analyzed by a series of experiments.The experimental results show that the existing JFC drilling fluid added with amidocyanogen silicone has good hydrophobicity,which can effectively inhibit the clay hydration slurry, and improve clay mineral tolerance.In the process of application, there will be no issues such as the rise of viscosity and the increase of filtration loss.So, it has little effect on its rheological property and filtration property. The results provide reference for wellbore stability and reservoir protection.