Abstract: With the development of renewable energy, power electronic devices account for an increasingly significant share in power generation, energy storage, and power transmission/distribution. As a core solution for enhancing grid coupling, the virtual synchronous generator (VSG) has become a research hotspot. However, in multi-VSG parallel systems, active power oscillations remain a critical challenge affecting system stability and dynamic performance. This paper conducts a systematic review of active power oscillations in multi-VSG parallel systems, covering their generation mechanisms, key influencing factors, and suppression strategies. It further discusses current research challenges and proposes potential future research directions.