The invention provides a preparation process of an inorganic diaphragm based on mesoporous material, which comprises the following steps of: dissolving silicon oxide and mesoporous material in a preset mass ratio in a solvent and uniformly stirring to obtain a suspension; adding a suitable amount of bind and dispersant into that suspension, and performing fully stirring at a preset stirring speedto obtain the inorganic coat slurry; coating a surface of that battery substrate with the inorganic coating slurry, and performing drying at a preset temperature for a period of time to prepare an electrode-supported inorganic diaphragm. The invention combines ceramic powder with mesoporous molecular sieve to prepare diaphragm slurry, which not only ensures high safety of inorganic diaphragm, butalso avoids defects of brittleness and polycrystallinity of diaphragm, and is beneficial to improving liquid-retaining capacity of diaphragm and energy density of battery. The synthesized diaphragm has the characteristics of ultra-light, good adhesion with the substrate, and good flexibility, can effectively avoid the problem that the mechanical properties of the diaphragm become worse when the inorganic diaphragm is made of a single ceramic material.