On October 22, 2010, in the Dagang Oilfield block of PetroChina, the Gangshen 64-1K well needed to be renovated. The sidetracking window hole at a depth of 2075 meters was 46 degrees. Since the well section is a window between double casing (oil casing and technical casing), conventional whipstock cannot meet the window requirement. Our company uses a new type of double-cylinder deflector to meet the technical problems of large well inclination, double casing and other window openings at one time. It is safe, reliable, efficient, and reduces construction costs. It has won unanimous praise in the industry.