In recent years, the controllability and flexibility of power electronic converters have made them widely used in AC power distribution systems. However, with the continuous increase of the penetration of power electronic equipment, the oscillation stability problem caused by high-penetration power electronics has become one of the key technical problems faced by the new power system. In actual AC power distribution systems, the sub/super-synchronous oscillation problems occurred frequently, which seriously affect the industrial production and stable operation of power grid. Therefore, an oscillation suppression method for power electronic AC distribution system based on weak point location was proposed in this paper. Through constructing the frequency-domain impedance network of power electronic AC power distribution system and establishing the node admittance matrix model of the system, the sub/super-synchronous stability of multi-machine system was analyzed based on the dominant eigenvalue. The participation factor matrix of the weak mode of the system was further calculated to determine the weak nodes of the system. The node coupling degree was defined to quantitatively evaluate the interaction between nodes. Finally, a DC voltage feedback active damping based oscillation suppression method was proposed. The effectiveness of the proposed method was verified by an example based on a practical power electronic AC power distribution system.