Abstract: In current measurement of the freeform spectacle lenses using wavefront sensor, the diameter of progressive addition lenses is usually larger than the receiving aperture of wavefront sensor, it is mainly used to measure the wavefront aberration of the lens by means of the sub-aperture stitching technique.In order to solve the problems of complicated operation and large amount of data processing in the measurement of the sub-aperture stitching technology, a method of beam expanding-shrinking system measurement for wavefront aberration of progressive addition lens was presented, through which the wavefront aberration within 22 mm diameter circular area of progressive addition lens could be got.In order to verify the reliability of the test, the measured defocus co-efficients in Zernike representation of wavefront aberration were transformed into spherical mirror degree, and compared with the spherical mirror degree measured by fringe deflection method. Results prove that the method based on the beam expanding-shrinking system is feasible.