A continuous angle standard device for the full circle (0° ~ 360°) is developed at the National Institute of Metrology, China. The self-calibration method of equal division average (EDA) with four reading heads is utilized for hardware compensation. The angle measurement accuracy of the standard device after compensation is smaller than 0. 1″. To further improve the angle measurement accuracy of the standard device, the mathematical model of the self-calibration error separation algorithm is derived from the harmonic angle based on the error characteristics, and the error separation method based on cross-calibration and the EDA method is proposed. Secondly, the Fourier series distribution of the original error of full combination separation and the full circle discrete angular position deviation after EDA compensation is analyzed quantitatively. And the error attenuation rate after EDA compensation is analyzed to achieve the optimal EDA compensation function. The inverse Fourier transform method is used to generate the continuous full circle (0° ~ 360°) angle compensation function. Finally, the laser interferometer is utilized to verify the accuracy of the full circle continuous angle standard in the small angle range, which is compared with the laser small angle benchmark of National Institute of Metrology. Experimental results show that the proposed method takes advantage of the high-precision measurement capability of the cross-calibration off-line. The compensated EDA angle measurement accuracy is close to the cross-calibration method within the continuous angle range of the full circle. This method can improve the calibration capability and limitations of self-calibration. The continuous full circle angle standard device is further improved.