Electrical energy router with common high- frequency AC bus have received more and more attention. Under the high-frequency switching action, the shifting inductor and the high-frequency transformer distributed capacitance form a resonant network, causing high-frequency oscillation problems. This paper takes the multi-port electric energy router with common high-frequency AC bus (HFB- EER) as the research object, high-frequency oscillation problems are analyzed and an equivalent mathematical model for the AC bus high-frequency oscillation problem is established, the mechanism of HFO and its influencing factors are also studied.