介绍研制成的一台移相式数字平面干涉仪，其孔径为Φ２４５ｍｍ，用液面作基准标定并消除仪器的系统误差，准确度优于λ／５０（峰谷值，λ＝０．６３２８μｍ）。利用计算机辅助干涉术，被测件口径可扩展到Φ５００ｍｍ。该仪器将用于建立高精度、大孔径平面波像差标准。文中阐述了光学干涉仪、移相器及精度校核等问题。 Introduced a developed phase - shift digital planar interferometer, the aperture of Φ245mm, with the liquid level as the benchmark calibration and eliminate the system error, the accuracy is better than λ / 50 (peak value, λ = 0.6328μm) . Using computer-assisted interferometry, the measured diameter can be expanded to Φ500mm. The instrument will be used to establish high-precision, large-aperture plane wave aberration standards. The paper describes the optical interferometer, phase shifter and accuracy check and other issues.