A local optimization method in the design of freeform surface lens based on non-imaging optics to achieve uniform illumination for LED source is proposed. In this design, the regular quadratic curve is adopted to replace the freeform curve of initial model, and the Scheme programming language and the optimization engine in the TracePro software are used in combination. In this way, a uniform illumination of LED is achieved. A Lambert emission of 1 mm×1 mm LED is used as simulation source. It is shown that the illumination efficiency of 80.89% and the uniformity of 95% within a field of view of ±15° are achieved at the target surface 1 m away from the source. Compared with the current global optimization method, the field-of-view and the illumination uniformity are improved significantly by this technique. It also possesses advantages of simplicity in process, less reliability requirement on initial model, and good versatility.