The invention relates to a photoelectric detector with a self-contained reference air chamber and a manufacturing method thereof. A TO socket of a TO-can photodetector is sealed with an optical element; the space between the TO socket and the optical element form a reference air chamber, whether the TO socket and the optical element are tightly welded is determined, if not, the TO-can photodetector after welding and the optical element are disposed in the detected gas environment, and the detected gas is filled into the reference gas chamber through a welding seam under the high pressure; thewelding seam is sealed through UV optical cement; after solidification of the UV optical cement, and two layers of moistureproof glue are coated on the welding seam; if tight welding is realized, a hole is made on a side wall of the optical element, and the detected gas is filled into the reference gas chamber through utilizing a needle; the hole is sealed through utilizing the UV optical cement,after solidification of the UV optical cement, two layers of moistureproof glue are coated. The photoelectric detector is advantaged in that the photoelectric detector is a key part of an optical spectrum absorption gas sensor, and integration and stability play an important role in ensuring measurement accuracy.