The invention provides a free-form surface lens for a projection-type light emitting diode (LED) automobile dipped headlight. The free-form surface lens is composed of two surfaces, wherein the first surface is a circular plane, and the second surface is a free-form surface; and a normal vector of a point on the free-form surface is obtained through a refraction law, a tangent plane is obtained through the normal vector, a coordinate of the point on the free-form surface is obtained by determining an intersection point of the tangent plane and a light ray, the light ray is obtained by refracting the next point through the first surface of the lens to enter into the free-form surface, the next point is obtained by intersecting the tangent plane of the last point and a straight line where the normal sector of the next point is positioned, coordinates of points of a curve on the free-form surface on a coordinate plane are obtained through iteration, and the obtained coordinates of the points are fitted into a curve and then rotated around a Z-axis by 360 degrees to obtain the final lens free-form surface. According to the free-form surface lens, trends and distribution of light rays are controlled through the lens free-form surface, so that light areas of the lens can meet the requirement of national standards for light distribution and illumination of the automobile dipped headlight.