In this paper a lateral shearing interferometer using double fooal-length wave-zone-plate (DFWZP) is proposed. The plate can easily be produced holographioally as shearing element. This interferometer is very suitable for the measurement of converging wavefront. It not only retains the advantages of the Ronchi grating testing method but can also obtain the interferograms of good contrast. It provides Variable shearing and does not require the replacement of DFWZP. This interferometer can obtain shearing shearing interferograms in any desired direction by translating the DFWZP in the DFWZP plane. Hence it can be used to test rotationally nonsymmetrio wavefronts. The fabricating and adjusting derivations of the DFWZP is one of the souzoes of measuring errors. The quality of the DFWZP oan be tested with the star point method.