Distributed generation (DG) in microgrid is generally connected through power electronic converter interface, which reduces the inertia of microgrid. The virtual synchronous generator (VSG) can provide inertia support for the microgrid. However, due to the inconsistent response speed to load changes, power frequency oscillation will occur between multiple DGs using VSG, and even cause the instability of the microgrid. To solve the above problems, a power frequency oscillation suppression strategy for microgrid with multiple VSGs is proposed considering the consistent second-order term. Firstly, the secondary control strategy of microgrid with multiple VSGs based on first-order consistency is established, and the mechanism of power oscillation between multiple VSGs is studied by using small signal analysis method. Then, the second-order term of consistency is introduced to provide damping for power frequency oscillation, and the adaptive gradient algorithm is used to optimize the second-order control coefficient to improve the suppression effect. Finally, the feasibility of the strategy is verified by a simulation example.