The invention provides a preparation method and application of an organic and inorganic hybrid additive. The organic and inorganic hybrid additive is formed by hybridizing hyperbranched polymer and calcium silicon composite oxide. The preparation method comprises the steps that a compound a and a compound b are subjected to ring opening polymerization under a catalyst, then, the polymerization product and a compound c are subjected to an esterification reaction, and the hyperbranched polymer is obtained; the hyperbranched polymer is dissolved in water, pH is adjusted to be 9-11, a calciferous inorganic component d and a silicious inorganic component e are added, a sufficient reaction is carried out under reaction conditions, and therefore the organic and inorganic hybrid additive is obtained. By means of the organic and inorganic hybrid additive, the early strength of cement materials can be improved, the water-reducing rate is high, the long-term strength of concrete is not affected, and meanwhile the conveying cost of an early strength agent is reduced.