The invention relates to a power grid oscillation starting device and an oscillation starting control method. The device comprises an oscillation starting loop, a first alternating current interface,a second alternating current interface and a high-precision measuring system. The method comprises the following steps of changing impedance and/or current accessed to a power supply object through the oscillation starting loop, and simultaneously causing system oscillation or resonance to construct system conditions for a stable boundary test of the power supply object; and measuring, calculatingand displaying the oscillation boundary value of the power supply object by using the high-precision measuring system. The technology of the power grid oscillation starting device and the oscillationstarting control method can simulate strong and weak power grids and cause system oscillation, is used for testing the reaction of a distributed power supply and a micro-grid in a oscillation starting system, further obtains the adapting capability to the strong and weak power grids and the self-stability boundary condition, and is vital to improving the adaptability and the stability of the tested equipment and reducing the oscillation of a power system with multi-power electronic access.