A high-pixel lens which increases a length of a front half includes: an aperture diaphragm S, a first lens piece L1, a second lens piece L2, a third lens piece L3, a fourth lens piece L4 and an optical filter in sequence from an object side to an image side, wherein the L1, the L2, the L3 and the L4 are all plastic aspheric lens pieces, wherein: the L1 is a biconvex lens piece having a positive focal power; the L2 is a meniscus lens piece having a negative focal power and being convex towards the image side; the L3 is a biconvex lens piece having a positive focal power, and at least one side of the L3 has an inflection point; and the L4 is a biconcave lens piece having a negative power, and at least one side of the L4 has at least one inflection point.