The invention provides an adjustable air cooling device. The adjustable air cooling device comprises air covers (1) and air cover fixing frames (2), wherein each of the air covers (1) is arranged at one end of the corresponding air cover fixing frame (2); at least one air duct (3) is formed in the side part of each of the air covers (1); an air intake connector (4) is arranged at the top of each of the air covers (1); one end of each of the air intake connectors (4) communicates with the corresponding air duct (3), and the other ends of the air intake connectors (4) are embedded in the air cover fixing frames (2) separately; locking buckles (5) are arranged on each of the air covers (1) in a symmetric manner; locking rings (6) are arranged on each of the air cover fixing frames (2) in a symmetric manner; each of the locking buckles (5) is connected with the corresponding locking ring (6) in a matched manner; and the two air cover fixing frames (2) are arranged on the two sides of a water cooling device separately. According to the adjustable air cooling device, the structure is simple, the assembly and disassembly are convenient, the annular cooling and drying of the surface of an extrusion molding part are realized, a good and uniform cooling effect is achieved, the wall thickness and mechanical property consistence of the extrusion molding part are better, and the performance and quality of products during the production process can be ensured easily.