The invention provides a four-quadrant current source converter based on an autotransformer. The four-quadrant current source converter comprises the autotransformer, an AC power source, an inductor, a first three-phase rectifier bridge, a second three-phase rectifier bridge and a DC harmonic injection circuit, wherein the first three-phase rectifier bridge is connected in parallel with the second three-phase rectifier bridge; and the input end of the autotransformer is connected with the output end of the AC power source via the inductor, the output end of the autotransformer is connected with the input end of the first three-phase rectifier bridge and the input end of the second three-phase rectifier bridge, and the output end of the first three-phase rectifier bridge and the output end of the second three-phase rectifier bridge are connected with the DC harmonic injection circuit. According to the invention, a main topology employs the autotransformer as a base, the DC injection circuit is connected through the two three-phase bridges, through controlling injection currents of a DC circuit, output currents of the autotransformer are modulated, and thus the purpose of inhibiting harmonic waves is realized.