Preparation method of polymine microcapsule capable of being used for sustained release of medicines

The invention discloses a preparation method of a polymine microcapsule capable of being used for sustained release of medicines. The preparation comprises the following steps: preparing a polymine aqueous solution at first; then measuring an organic solvent and an oil soluble surfactant, and dissolving the oil soluble surfactant in the organic solvent; adding the polymine aqueous solution, the organic solvent and the oil soluble surfactant into a reaction container, and stirring at a low temperature by using a high-speed homogenizer to form water-in-oil emulsion; and dropwise adding an organic solvent containing a crosslinking agent into the water-in-oil emulsion while stirring at a low temperature, and centrifuging to remove the organic solvent and the surfactant from the reaction solution after reaction to obtain the polymine microcapsule capable of being used for sustained release of medicines. The minimum particle size of the microcapsule obtained by the method disclosed by the invention can be maintained at 700-1000nm; and the human body temperature of 37 DEG C can be simulated, and in a tumor tissue acid environment (PBS buffer solution), the maximum release rate of a medicine can reach 65%.