In order to increase the illuminance uniformity of the source used in the liquid crystal display(LCD) detection, based on nonimaging optics, a method of a light emitting diode (LED) source with large aperture and small view angle is proposed in this paper. The illumination system of this source is realized by array of LEDs and the lenses. For a single LED, Fresnel lens is designed to collimate the beam with small view anglethen, the optimal distance of the array is obtained by deducing the uniform illumination condition and optimizing it with TracePro. Finally, the uniform rectangular illumination is achieved through splicing superposition the spot on the illuminating surface. The illumination source consists of 12×9 optical units which are arranged in uniform rectangle, and the distance between every two optical units is 30 mm. The simulation results show that the viewing angle of the source is less than ±10°. At the target surface 170 mm away from the source, the average illuminance is greater than 45000 lx, and the nonuniformity is 3.8%. All of the indexes meet the design requirements. Comparing with the existed source, the arrayed source designed in this paper has obvious advantages whether on the average illuminance or the illuminance uniformity.