The traditional wide-area synchronous measurement technology based on GPS / Beidou is vulnerable to hostile cyber-attacks, and its reliability is difficult to guarantee. In order to solve this problem, this paper utilizes the pulsar signal high accuracy characteristics of periodic pulse and immunity to existing cyber-attacks to establish a new adaptive synchronous sampling method. Firstly, polyphase filtering,de-dispersion and period folding are performed on the pulsar signal received by the radio telescope to obtain pulse profile. Then, the local crystal oscillator frequency is monitored with the least square method, and the time control interval is dynamically adjusted and controlled to realize adaptive synchronized sampling. To verify the effectiveness of the algorithm, this paper uses the observation data of the pulsar J0437- 4715 to generate synchronization signals and realize the synchronized measurement of the power grid signal. The recursive discrete Fourier transform algorithm is applied to calculate the phase angle and frequency of the sampling data, and the obtained average errors of phase angle and frequency are -9. 75×10 -5 ° and 9. 83×10 -7 Hz, respectively, which verifies the effectiveness of the proposed adaptive synchronized sampling method.