The present application provides a preparation method for a dendritic or hyperbranched polymer, comprising : adding components in a reaction system to a hypergravity reactor; and controlling a reaction temperature and a hypergravity level to prepare the required dendritic or hyperbranched polymer. Compared with the dendritic or hyperbranched polymer synthesized by a traditional process, the present application enhances a mass transfer process of a polymer molecule, improves the mass transfer efficiency, greatly shortens a reaction period, and ensures that the product purity is not reduced; the present application further has advantages such as low energy consumption, small space occupied by a device, large operation elasticity, simple production procedure, high efficiency, and low material consumption.