The invention discloses an automobile fuel quantity sensor. The automobile fuel quantity sensor includes a sensor body, wherein the outer surface of the sensor body is sequentially coated with a ceramic-based composite coating, an aluminum oxide coating and a glass cloth coating from the inside to the outside; the lower end of the sensor body is provided with an oil inlet hole, and the bottom of the sensor body, at the outer surface of the oil inlet hole, is fixedly connected to a filter mesh; the upper end of the sensor body is provided with venting holes, and the top end of the sensor body is fixedly connected with an electric box; and the left side of the electric box is movably connected with a lead wire. For the automobile fuel quantity sensor, the ceramic-based composite coating, thealuminum oxide coating and the glass cloth coating are coated on the outer surface of the sensor body from the inside to the outside, so that the automobile fuel quantity sensor effectively improvesthe corrosion resistance, oxidation resistance and high temperature resistance of the sensor body and solves the problem that because the automobile fuel quantity sensor is in contact with diesel or gasoline in a fuel tank for a long time, the sensor itself is damaged and then the measurement accuracy of the sensor is reduced.