The key technology of accurately acquiring synchronization commands is proposed by this paper, when analyzed the practical technical problems existing in the use of surge arrester monitoring system at substation and introduced the overall implementation scheme of surge arrester monitoring system. Firstly, a new digital filtering method is proposed by analyzing the pipeline filtering method and step-size filtering method, and the simulation and verification are carried out. Secondly, the synchronous phase compensation of each arrester acquisition unit is analyzed by real-time acquisition of the crystal vibration interval of the arrester monitoring unit in the monitoring system, and met the test requirements. The solution proposed by the paper, has been realized and verified in the product, which has certain reference value for solving the key technology of arrester acquisition unit.