Due to low temperature and harsh environment, there is ice coating problem in distribution network lines, which has great harm to the reliability of power supply system. Hydrophobic film or coating can be used to effectively prevent the ice coating problem. Preparation of hydrophobic coatings for adaptive circuits with high efficiency and low cost is a practical subject. A hydrophobic surface was prepared by plasma modification of polydimethylsiloxane (PDMS) with mixed gas of He(Ar)/CH4/C4F8. The surface can cover the outer layer of the circuit to provide hydrophobic properties. The effects of discharge voltage level, distance between discharge electrodes, discharge time and discharge frequency on the preparation of hydrophobic surface modified by plasma were studied. COMSOL software was used to analyze the electric field intensity distribution of PDMS microchannel and explore the distribution of plasma. Based on the simulation results, physical experiments were designed to verify and analyze the mechanism of each factor[HJ] by measuring the contact angle, roughness and surface topography of PDMS modified surface and taking gas discharge images. Finally, suitable conditions were selected to successfully prepare the PDMS hydrophobic surface in line with expectations, and its good stability was tested.