The invention discloses a control method and a control system for hybrid MMC uninterrupted operation. The control method comprises the following steps: acquiring the alternating current output voltagereference values of each phase of upper and lower bridge arms, acquiring a direct current voltage reference value, acquiring the negative sequence frequency-doubled circulating current restraint reference voltage of each phase of upper and lower bridge arms, acquiring the zero sequence circulating current compensating potential reference value, and generating a driving signal. The control systemcomprises an alternating current control device, a direct current control device, a negative sequence circulating current restraint control device and a driving signal synthesis device which are usedfor acquiring the alternating current output voltage reference values of each phase of upper and lower bridge arms, the direct current voltage reference value, the negative sequence frequency-doubledcirculating current restraint reference voltage of each phase of upper and lower bridge arms, the zero sequence circulating current compensating potential reference value and the driving signal. Alternating current positive and negative sequence current can be uniformly controlled, alternating current negative sequence current and bridge arm zero sequence ring current are restricted, direct current side current is controlled, and uninterrupted operation is finally realized.