Integral imaging needs to record the spatial information of three-dimensional (3D) objects from different perspectives, therefore the computation is large and cost a long time by computer-generated method. To solve this problem, we present a fast elemental image array generation method by using window interception. The sampling model is established by simulating the structure of the lenslet array, and the elemental images of the virtual 3D object, corresponding to each virtual lens, are calculated based on optics parameters of the display platform. Then, the window interception is used to generate the elemental image array. The elemental image array with any aperture and any arranging structure can be generated by changing the sampling points and the window function. We build an integral imaging display platform based on LED and design the lenslet arrays with the shape of square, hexagonal and circular aperture. Different 3D models are used to compare the processing time and display effect. Experimental results show that without reducing the 3D image quality, the proposed method is faster when the resolution of elemental image is higher than the sampling rate of the lenslet array.