A new algorithm of wavefront reconstruction based on the cyclic radial shearing interferomerter is given This is a technique that the actual wavefront can be reconstructed directly and accurately from the distribution of phase difference which is obtained from the radial shearing pattern by Fourier transform profilometry. By the numerical calculation and experiments, it is concluded that the new algorithm is credible and the accuracy of wavefront reconstruction with different amplification ratio is basically same based on this interferometer. It shows that this algorithm can be used to reconstruct accurately the distorted wavefront of ICF. A example of test of step structure is presented with different amplification ratio with He Ne laser.