The invention discloses an efficient one-step regeneration method taking a root system of broussonetia papyrifera as an explant. The method comprises the following steps: S1, adventitious bud induction: selecting a root system of a broussonetia papyrifera aseptic seedling as the explant, cutting out a wound, inoculating the explant to an adventitious bud induction medium, and conducting inducing to form adventitious buds; and S2, rooting culture: cutting the adventitious buds in the step S1, inoculating the adventitious buds to a rooting culture medium for rooting induction, and culturing the adventitious buds until the adventitious buds root to form regenerated seedlings. According to the method, the broussonetia papyrifera in-vitro regeneration plant is successfully obtained through the steps of adventitious bud induction, adventitious bud rooting, domestication and transplanting and the like by taking the root system of the broussonetia papyrifera as the explant, and compared with a culture method taking other broussonetia papyrifera tissues as explants, the method is simpler and more convenient to operate, wider in material taking range and more efficient in propagation.