Abstract: Grid-connected converters have been widely used in the renewable energy generations such as wind power and PV, which makes the conventional power system more flexible and controllable. However, the resonance issues bought by the power converters have been a great threat to the safety and stability of power system operation. This paper presented an overview on analysis, detection and mitigation of resonance in the grid-connected converter systems. The structure and control strategy of grid-connected converter systems were introduced first. Then modeling and stability analysis methods of grid-connected converter systems were also compared, especially the state-space method and the impedance-based method. By using the impedance-based method, this paper analyzed different kinds of resonance mechanism in the grid-connected converter systems. Then different kinds of resonance detection methods were compared, including their advantages and restricts. At last, this paper summarized and classified several kinds of the resonance mitigation methods and points out the advantages of the new active damper.