The invention discloses a preparation method and treatment method for an all-silicon molecular sieve, the all-silicon molecular sieve, and a catalyst and application thereof, belonging to the field ofsynthesis of catalytic materials. The preparation method comprises the following steps: (1) mixing a template, tetraalkoxysilane and water, subjecting the obtained mixture to hydrolysis and removingalcohol; and (2) mixing a product obtained in the step (1) with a compound and subjecting the obtained mixture to crystallization, wherein the compound has a structure as shown in a formula (I) whichis described in the specification, i in the formula is any integer selected from a group consisting of 1 to 10, R1, R2 and R3 in the formula are independently selected from a group consisting of a methyl group, an ethyl group, a propyl group and a butyl group, and R4 and R5 in the formula are independently organic groups consisting of 1 to 20 carbon atoms, 0 to 5 nitrogen atoms, 0 to 3 oxygen atoms and hydrogen, or R4 is connected with R5 to form a five-to-ten-membered nitrogen heterocycle or nitrogen oxygen heterocycle. The all-silicon mesoporous molecular sieve provided by the invention hasgreater specific surface area and mesoporous volume, improves the diffusion of a macro-molecular substrate in the pore channels of the molecular sieve, and is substantially improved in catalytic activity.