The invention relates to an integrated detection system and method for energy storage converter grid-connected and off-grid characteristics. A grid-connected converter unit and a simulation converter unit are comprised. The grid-connected converter unit comprises a rectifier module and an LCL filter. The alternating current side of the rectifier module is connected with a power grid through the LCL filter. The direct current side is connected with the direct current side of the simulation converter unit. The alternating current side of the simulation converter unit is connected with a detected energy storage converter. According to the technical scheme provided by the invention, the topology of the integrated detection system for energy storage converter grid-connected/off-grid characteristics is provided, which improves the effectiveness of the energy storage converter detection system and the power grid simulation fitting.