The invention discloses an Al-BiOCl aluminum-based composite hydrogen production material and a preparation method thereof.The aluminum-based composite material is prepared by conducting ball milling on aluminum powder and a BiOCl additive.The preparation method comprises the steps that the aluminum powder and BiOCl are added into a ball-milling pot according to the mass proportion, wherein m(Al):m(BiOCl) is x:(1-x), and x ranges from 0.5 to 0.95; grinding balls are added on the condition that the ratio of the milling balls to the materials is (30-120):1, and sealing is conducted; the ball-milling pot containing the materials is put into a ball mill, ball milling conditions are set, and ball milling is conducted, wherein the rotation speed of the ball mill ranges from 100 rpm to 250 rpm, and the ball milling time ranges from 1 h to 10 h; the prepared aluminum-based composite material is taken out.The preparation technology is simple and convenient, the raw materials are nonhazardous and low in cost, real-time production is achieved, carrying is convenient, and the hydrogen production method is green, environmentally friendly, efficient and suitable for application in the aspects of fuel cell hydrogen supply and the like.