An audio jack includes an insulative housing, and a plurality of contacts retained to the housing. The housing forms a main body, a mating port with a mating cavity therein. The main body forms a plurality of contacts receiving passageways extending from a bottom side of the housing and transversely communicating with the mating cavity. The contact has a contacting section extending into the mating cavity, and a soldering leg extending outside of the housing. A bottom cover is attached upon the bottom side of the housing. A waterproof plate is applied upon a bottom face of the bottom cover to seal the gaps among the housing the bottom cover and the soldering legs.