A two-element f-θ lens used for a micro-electro mechanical system (MEMS) laser scanning unit includes a first lens and a second lens, the first lens is a positive refraction meniscus lens of which the convex surface is disposed on a side of a MEMS mirror, the second lens is a positive refraction meniscus lens of which the convex surface is disposed on the side of the MEMS mirror, at least one optical surface is an Aspherical surface in both main scanning direction and sub scanning direction, and satisfies special optical conditions. The two-element f-θ lens corrects the nonlinear relationship between scanned angle and time into the linear relationship between image spot distances and time. The two-element f-θ lens focuses the scan light to the target in the main scanning and sub scanning directions, such that the purpose of the scanning linearity effect and the high resolution scanning can be achieved.