The invention relates to instant outer membrane type hydrophobic water control sand and a preparation process thereof. The instant outer membrane type hydrophobic water control sand comprises quartz sand or ceramsite, a hydrophobic layer and an instant outer membrane, wherein the quartz sand or ceramsite is coated by the hydrophobic layer and the instant outer membrane in sequence. The preparation process comprises the steps of (A) immersing the surface of the quartz sand or the ceramsite in industrial alcohol, stirring, cleaning, and drying at a room temperature; (B) mixing the surface-cleaned quartz sand or ceramsite with a fluorosilicon resin (FSI-100) and tetraethoxysilane, and mixing into the water control sand having the hydrophobic layer; and (C) immersing and coating the hydrophobic water control sand by using a polyvinyl akohol solution with a mass concentration of 3-8% at a temperature of 75-85 DEG C, and cooling to form the instant outer membrane. The preparation process has the characteristics of realizing effective water control while preventing the sand, reducing the general water percentage of oil wells, increasing crude oil output, preventing stuck pumps during sand prevention constructions, etc. The preparation process is widely used in the sand prevention and water control of petroleum exploitation.