The invention discloses a three-phase rectifying circuit suitable for use in an unbalanced power grid. The three-phase rectifying circuit is used for converting three-phase AC power into DC power, andcomprises a three-phase rectifier bridge arm circuit connected to a three-phase AC power supply and configured to rectify the three-phase AC power; and a coupling circuit including a first capacitorC1, a second capacitor C2, an inductor L, and a load resistor Rload on a DC side, wherein the first capacitor C1 and the second capacitor C2 are connected in series and then are connected to the two output ends of the three-phase rectifier bridge arm circuit respectively, one end of the inductor L is connected to the output end of one phase of the three-phase AC power supply; the other end of theinductor L is connected between the first capacitor C1 and the second capacitor C2, and the two ends of the load resistor Rload are connected to the two output ends of the three-phase rectifier bridgearm circuit respectively. The invention provides the coupling circuit to which the low-order oscillation power generated in the unbalanced power grid is transferred, thereby maintaining the DC-side voltage stability, improving the power quality of the DC side, and maintaining the normal operation of the DC-side load.