A production process of an insole, the steps of: cleaning an insole mold; spraying an oily release agent into a cavity of an upper mold and a cavity of a lower mold of the mold; uniformly fixing cloth in the cavity of the upper mold; injecting shoe material into the cavity of the lower mold of the mold, covering the upper mold of the mold to lock the upper mold and the lower mold after finishing injecting shoe material, and then placing the mold in an oven for baking, opening the upper mold of the mold after finishing baking, and taking out the insole. The production process of an insole is simple in process and high in yield rate, and uses the characteristics that the cloth and the raw material have good adhesion to directly put the cloth into the mold to take shape, thereby eliminating a glue adhesion process.