To measure the Radius of Curvature (ROC) of an optical element accurately, a novel interferometric testing approach by combining a Reflective-type Computer-generated-holography (RTCGH) and the wavelength phase-shifting technology was proposed to measure the ROCs of spherical optical surfaces. In measurement, the RTCGH was used as a reference to calibrate the ROC of the reference surface of a transmission sphere lens. Meanwhile, the lengths of interferometric cavities were measured by using wavelength phase-shifting. Then, the ROC to be measured could be calculated by above data. The system structure and the measuring principle of proposed method were described firstly. And then, combining with an example, the measuring uncertainty was analyzed in detail by the theoretical derivation and computer simulation. Finally, a verification experiment was performed by using a commercial wavelength phase-shifting interferometer in our laboratory. The ROC of an optical spherical sample with an aperture of 100 mm was tested by the method and the test result is 157.108 3 mm. For comparison and validation, the sample was also tested by a spherometer and the relative error is less than 0.02%. Compared with other non-contact ROC measurement methods, this testing way has advantages of less error sources, high measuring precision and convenient operation.