The invention discloses a current source converter minimum DC ripple modulation method. The method comprises the following steps: various parameters such as the converter AC voltage amplitude Vtm, the converter AC A-phase voltage initial phase gamma, the modulation ratio m and the reference current angular displacement initial value theta0 of the system are calculated. Through selecting the most proper modulation mode, the DC ripple reaches the minimum, the performance of the converter is optimized, and the service life of the system is prolonged. Compared with the traditional ripple suppression method, the new method does not need to increase the DC inductance nor the switching loss, the method only needs to improve the modulation algorithm of the converter, and great superiority exists; the limitation of a converter AC-side power factor angle does not exist, the problem of time point switching does not exist, the application range is wider, and the realization is simpler.