The invention discloses a Pickering emulsion with uniform particle size and a preparation method and application thereof. The uniform and stable Pickering emulsion is formed by using a solid particle as a stabilizing agent, dispersing the solid particle in a water (or oil) phase, then subjecting the dispersed solid particle and an oil (or water) phase to emulsification and then allowing a formed pre-emulsion to pass through a membrane emulsification apparatus. Or the uniform and stable Pickering emulsion is formed by allowing a dispersed phase (water phase or oil phase) to pass through membrane holes under pressing and then to enter a continuous phase (oil phase or water phase) with the dispersed solid particle and then enabling an emulsion to fall off from the membrane holes under the action of external force. The preparation method is simple; through adjusting of the proportion of water and oil phases, particle concentration, the size of the particle and a microporous membrane, the properties of the emulsion are regulated and controlled, the prepared emulsion is stable and has a uniform and controllable particle size and enhanced stability, usage of a traditional emulsifier is avoided, and toxicity to human bodies and environmental pollution can be reduced; and the emulsion can be extensively used in fields like biological medicine, cosmetics, food, petroleum and waste water treatment.