In order to solve shortcomings such as technology complexity, high cost and long cycle in the traditional microlens array, a new method to fabricate microlens array with low cost, high efficiency has been studied. The microlens array main mold structure is made with the main optical axis parallel to the silicon base , which uses SU-8 negative photoresist mold structure material as the material of main mold structure and two tilte-exposure technology. Polydimethylsiloxane (PDMS) soft lithography and NOA73 UV-exposure technology are taken to copy the main mold structure, and NOA73 microlens array and PDMS microlens array are made successively. The surface topography of the microlens array is observed by confocal microscope and an optical detection platform is built to test the imaging effect of the microlens array. The result shows that NOA73 microlens array has better optical characteristics. The microlens array has better imaging effect and surface topography with above technology process. It has advantages such as good repeatability, short processing cycle, and can be integrated in the micro-flow cytometry instrument to process fluorescence detection of the sample flow, which can enhance the detection precision.