Provided are a multi-channel optical subassembly structure allowing an optical unit including a light source photodetector chip to be fixed through an alignment jig after active alignment is performed on an individual or single light source photodetector chip by using the alignment jig capable of electrical coupling and one electrode pad and the other electrode pad of a thermoelectric element, which are wire-bonded, capable of performing active alignment for each light source photodetector chip, that is, for each channel, capable of replacing the optical unit and the alignment jig when a problem occurs in some or all channels, capable of improving optical coupling efficiency for each channel, and capable of addressing a time-consuming and economically expensive work in which an optical subassembly is discarded when some channels fail, and a method of packaging the structure.