Abstract: This paper proposes a method of measuringdisplacement by ultrasonic speckle interferometry. Base on the digitalinterferometry method and phase-shift---frequency-shift principle,formulas for theultrasonic speckle digital interferential measurement are deduced.In order to verify the theoretical results, an experiment of measuringin-plane and out-of-plane displacements of an aluminous specimen isperformed. The experimental results indicate that the theoretical analyses arecorrect and the method can be applied in measuring displacementsand deformations.