Aiming at the problem of low precision and stability of traditional phase shifting methods, a high precision adaptive digital phase shifting method is proposed. The method is based on stochastic approximation algorithm and active RC phase shifting circuit to construct a closedloop control system. Configuring a highprecision digital potentiometer via FPGA, then detect the actual output phase and use it as an observation of the stochastic approximation algorithm. After many iterations, the potentiometer resistance is calculated and the output phase value gradually approaches the set phase value. The experimental results of phase shift accuracy and stability show that within the adjustable range of the digital potentiometer, the phase shift error does not exceed ±03°, and the phase shift error does not exceed ±025° for at least 11 hours. The phase shift error does not exceed ±03° during a rapid change in ambient temperature of approximately 20℃. Practical application experiments show that the method has good robustness and practicability. This adaptive digital phase shift provides a new method for high precision phase shifting.