The invention relates to a converter-based low voltage ride through control system of a wind generating set, comprising a converter, a converter controller and a low voltage ride through main controller, wherein the converter and an auxiliary circuit breaker are connected in series to form a controlled branch circuit; a main circuit breaker between the wind generating set and a grid is connected in parallel with the controlled branch circuit; a direct current positive electrode bus bar and a direct current negative electrode bus bar are arranged between a rectifier and an inverter; a capacitor and an unloading resistor are connected between the direct current positive electrode bus bar and the direct current negative electrode bus bar; the unloading resistor and the capacitor are connected in parallel; the unloading resistor and a controlled valve are connected in series; the controlled valve is connected with the converter controller; a grid end is connected to an alternating currentvoltage detector; a direct current voltage detector is connected between the direct current positive electrode bus bar and the direct current negative electrode bus bar; the alternating current voltage detector and the direct current voltage detector are both connected with the low voltage ride through main controller; and the low voltage ride through main controller is connected with the converter controller, the main circuit breaker and the auxiliary circuit breaker. The invention is effectively adapted to occasions where the depth voltage dips and has favorable stability.