A method of shape measurement based on the relationship between displacement measurement and shape measurement is presented. When the shape of an object is measured by using electronic speckle pattern interferometry (ESPI), the test object tilting with a small angle will introduce an additional height difference and produce a carrier pattern. The relationship between the tilting angle and the additional height difference is analyzed. Then the relationship between the phase of the test object and the height of object′s surface is obtained. The phase of the test object can be extracted by Fourier transform. A surface shape of a small ball is tested by using this method. The results indicate that the sensitivity of this method is high when the carrier pattern on an object surface is produced and object surface shape is measued.