The invention discloses a frequency converter power electronics controllable loading method based on a grid connected inverter. In a present frequency converter test, a dissipating energy type load completely wastes the electricity energy in a test process, and is difficult to accurately simulate load characteristics of the subsidiary engine of the frequency converter. In the method, the output terminal of a frequency converter is directly in connection with a three-phase grid connected inverter to be used as the artificial load of the frequency converter; the main circuit structure successively comprises a front transformer, an uncontrolled rectifier, an intermediate DC capacitor, an inverter, a filter and a rear transformer from front to back; different current given signals are given to the three-phase grid connected inverter to stimulate different load current characteristics; and the three-phase grid connected inverter is controlled by employing the current inner loop strategy based on a PI regulator in a two-phase rotating coordinate system. The method can be used in a high power frequency converter test, and realize reactive power balance control; in a whole process, almost all energy can be fed back to a power grid.