The invention provides a method and system for restraining power distribution network load busbar voltage fluctuations. During load busbar voltage negative fluctuations, load busbar voltage fluctuations are restrained by adjusting output power of a distributed power source, if the output power of the distributed power source can still not restrain load busbar voltage fluctuations within the allowable range, the resistance and reactance are adjusted by adopting a flexible circuit, and load busbar voltage fluctuations are restrained; if load busbar voltage fluctuates forwards, load busbar voltage fluctuations are restrained by adopting flexible loads; if the adopted flexible loads cannot restrain the load busbar voltage fluctuations, load busbar voltage fluctuations are restrained by reducing the output power of distributed generation. According to the method and system for restraining power distribution network load busbar voltage fluctuations, the utilization ratio of renewable energy sources is increased, and load busbar voltage fluctuations are effectively restrained during load busbar voltage fluctuations; while the requirement for voltage of loads is met, the flexibility of restraining the load busbar voltage fluctuations is improved, and stable operation of a power grid is ensured.