Spliting performance of two parallel plates is analyzed and a design method is presented to optimize their spliting performance. Two parallel plates parallel to each other split one incident laser beam into multiple beams which are detected by a CCD camera. Because of the use of CCD camera,difference of maximum power density between received laser faculae (DMPF) should be made as little as possible. Effect of distance between plates and incident angle on difference of laser faculae is analyzed. And the calculation results show that reasonable selection of distance between plates and incident angle can minimize DMPF. The optimum distance between plates increases as Rayleigh length of laser beam increases while the optimum incident angle keeps stable under the condition of fixed coated film and fixed central wavelength of laser beam. And DMPF under corresponding optimum conditions fluctuates as Rayleigh length increases.