On the basis of our papers, a new wedge plate shearing interferometer has been developed to evaluate and measure collimation, divergence and other parameters of laser beams and the amount of defocusing of systems of collimator and beam expander. It also can be used to test wavefront aberrations and to adjust optical systems. This is an ordinary shear plate interferometer but in order to obtain a quantitative result, it didn't apply the conventional method which is used to measure fringe width and angle, and it is impossible to give a high precision results. A reliable and high precise method is measuring the rotating angle of the plate about the center normal line of the front surface of the plate. Above method belongs to one-dimensional shearing interference. In order to test rotational asymmetric wavefront, the plate can be rotated about the optical axis of the incident laser beam. As a result any orientation shear (horizontally, vertically and at 45 degree or other angles) can be given. This instrument allows quick and easy measurement of the defocus, and third order spherical aberration, coma, and astigmatism in the system.