This invention belongs to the field of fire extinguishing materials and their preparation technology, and provides a fire extinguishing microcapsule and its microfluidic controllable preparation method. The preparation method is characterized by the following steps: (1) preparing fluids of each phase, (2) preparing a dual
emulsion using a microfluidic device, (3) collecting and sealing the dual
emulsion in a collection container, controlling the axis of the collection container to be horizontal, and controlling the collection container to rotate around its axis for 1 to 15 minutes, applying light to solidify the outer shell of the dual
emulsion droplets while maintaining the rotation of the collection container, cleaning, and
drying to obtain the final product. The fire extinguishing microcapsule prepared by this method consists of an outer shell and a
liquid fluorine-containing fire extinguishing agent encapsulated within the outer shell. The outer shell of the fire extinguishing microcapsule has a uniform thickness, and the eccentricity between the outer shell and the core is less than 0.1. The method of this invention can achieve precise customization of fire extinguishing microcapsules according to the differentiated fire characteristics of different application scenarios, and can improve the concentricity between the core and the outer shell of existing fire extinguishing microcapsules.