The invention belongs to the researching field of nano-porous materials and particularly relates to micron particle mesoporous silicon dioxide, and preparation and an application thereof. A preparation method includes: 1) adding deionized water, glacial acetic acid, a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123, PEO-PPO-PEO), and n-butanol into a container, fully stirring the mixture until the P123 is completely dissolved, adding chitosan, continuously fully stirring the mixture until the chitosan is dissolved completely, then adding ethyl orthosilicate with continuous stirring until the reaction is completed; 2) after the reaction is completed, allowing the product to stand in a drying box; 3) separating and calcining the product to obtain the micronparticle mesoporous silicon dioxide.