Abstract: As the low voltage and small power capacity of hybrid AC/DC microgrid, the case which causes harmonic disturbance on DC side is less, therefore, there is no need to configure DC harmonic protection as the DC transmission field. However, the influence of AC disturbances caused by AC unbalanced faults on the DC system should not be neglected. The influence of disturbances on DC system, which is caused by AC unbalanced fault, was analyzed deeply, and the generation principle of first and second harmonic were studied firstly. And then, combined with three typical distributed generation（DG） control strategies, the response of DG control system to AC harmonic disturbances was analyzed, and the inner-loop reference current expression with perturbation component was proposed to analyze the influence. After that, simulation tests based on PSCAD/EMTDC were carried out to analysis the response of DC side and verify the above theoretical analysis. Finally, combined with the influence of AC disturbances, the suggestions for the design of hybrid microgrid protection system were proposed.