The invention provides a reactive power control method and device of a four-quadrant current source converter. The reactive power control method comprises the steps of obtaining a reference current imaginary part value and an actual current imaginary part value at an AC (Alternating Current) side of the four-quadrant current source converter; obtaining a triggering angle control quantity based on the difference value between the reference current imaginary part value and the actual current imaginary part value; and controlling the reactive power of the four-quadrant current source converter by adjusting the triggering angle control quantity. The reactive power control method and device of the four-quadrant current source converter solve the problems in the prior art that relatively big switching loss is resulted when a PWM control technology is adopted for reactive power control of the current source converter and relatively great stress may be generated for a switch device by the current source type converter when the current is cut off at a high frequency.