The invention discloses a manufacturing method for a constructional engineering machining workshop with a top cap being capable of rising and falling. The manufacturing method comprises the following steps that (1) the bottoms of a plurality of workshop vertical pillars are connected with workshop bottom beams, and workshop top beams are connected with the top ends of the workshop vertical pillars; (2) locking pins are arranged on the appointed height positions of the tops of the workshop vertical pillars, and locking spanners are arranged at the bottoms of the workshop vertical pillars; and (3) a lifting device is arranged, the top cap is lifted to an appointed height along the workshop vertical pillars, and the locking spanners control the locking pins to lock the top cap to the workshop vertical pillars, wherein the top cap comprises top cap bodies and top cap supporting seats connected with the top cap bodies and the workshop vertical pillars. According to the scheme, when a windy day or a typhoon day comes, the top cap falls to the ground and is effectively prevented from being damaged by typhoon; and the top cap and a frame are manufactured in a segmented mode, on-site assembly is achieved, setting up and disassembly are convenient and flexible, the constructional engineering machining workshop can be recycled for many times, the comprehensive cost is low, and more economic and more environmentally friendly effects are achieved.