Abstract: A handheld mobile device casing and a molding method of the same includes manufacturing a glass part and a supporting part. The glass part is used as a sight window on the handheld mobile device casing, and the supporting part is used to support the glass part. The glass part is placed on the supporting part in a staggered manner, which is to say, one end of the supporting part is exposed out of the glass part. The injection molding is performed to form a handheld mobile device casing that encapsulates the glass part and supporting part. With that molding method, the boundary of the sight window can be tightly coupled to the casing, without any offset or clearance. The glass sight window has high hardness and is wear resistant. The molding process is easy to operate, and the subsequent assembly process can be simplified.