Abstract: According to the design of three-in-one composite achromatic wave plate, an infrared composite achromatic /4 wave plate made of quartz was designed, which could be used in optical communication wave band. We further analyzed and tested the wave plate phase delay and composite angle which were the important factors influencing the achromatism scope, and put forward an optimum design scheme. Theoretical analysis and experimental result show that by adjusting the wave plate phase delay or composite angle, the maximum delay deviation for 1/4 composite achromatic wave plate achieves 5% in the wavelength range of 900 nm~1 800 nm with the central wavelength of 1 400 nm,which meets the achromatic requirements; in the optical communication wave band of 1 200 nm~1 600 nm, the maximum delay deviation achieves only 3.2%.