Proposed, justified and tested measuring of beam spatial coherence based on the detection of an interference visibility of the two reflected beams from the rotated plane-parallel plates. Hie specificity of measuring consists in dependence of the interference contrast from the longitudinal time delay and transverse shift of named replicas simultaneously. Accurate measurement of the angular position of the rotated plate and the amplitude distribution of interference minimaxes allows determining the beam coherence and optical parameters of used plates.