Abstract: In the field of high-precision DC output calibration of testing instruments and the development of precision measurement and measuring systems, it is essential to investigate strategies for improving the accuracy and resolution of DC standard sources and achieving the localization of precision adjustable DC standard sources. This paper presents the development of a precision adjustable DC standard source that uses a dual Pulse Width Modulation (PWM) synthesis voltage division regulation mode to achieve a resolution of 0.1 µV for the output DC voltage. By utilizing temperature compensation, precise phase inversion, drift-free filtering, and current compensation technology, the standard source was able to achieve an output uncertainty index of 4 ppm. Furthermore, a compensation correction algorithm was developed to improve the output accuracy. Experimental results confirm that the developed DC standard source operates reliably and stably over extended periods, making it suitable for high-performance DC reference requirements.