Laser transmitting wavefront is near diffraction-limited in space laser communication. Wavefront measurement is the basis of system adjustment and testing. Optical plate interferometer is a traditional valid method for wavefront sensing but it is invalid to meet the needs of measuring the wavefront of wave height less than 0.3 wavelength, aperture over 100 mm and laser diode coherence length short. Lateral double shearing laser interferometer is designed based on Maeh-Zehnder interferometer for the application. It includes two plane lens and four mirrors with one of which is vertically divided into two parts. The two parts turn around vertical line oppositely to be a small angle of several seconds between them. The wavefront aberration can be differentially analyzed from the fringes of the two parts and the accuracy is improved. The interferometer of 290 mm diameter suited for short-coherence laser is developed. Optical paths of the interference are equal length that is useful for laser diode etc. The wavefront of a tuning laser is measured by the interferometer. The experimental interferograms are analyzed with the software. The value of the wave height (PV) is 1.0 wavelength.