Abstract: The accuracy of Embedded Flash (E; Flash) internal high voltage is crucial to its efficiency of reading, programming and erasing. In order to minimize the high voltage error of EFlash IP, the circuit reserved adjustable interface to adjust the value of internal high voltage. By putting forward the algorithm of automatic detection and designing the self-test circuit integrating automatic detection and calibration, the purpose of high voltage calibration can be achieved quickly. The experiment takes EFlash with a storage capacity of 2 M as the object to reduce the calibration time from 3 s to 30 ms.