The present invention provides a mounting structure of an optical connector receptacle for fixing the optical connector into a through hole of a metal housing. The mounting structure has a main plate leaning against a first surface of the receptacle, and a pair of side plate portions leaning against two second surfaces respectively connected to the first surface. Each side plate portion comprises a first side plate connected to the main plate, a connecting plate having one side connected to the first side plate, and a second side plate connected to another side of the connecting plate so that an indentation structure is formed, wherein the first side plate or the second side plate has a first extending element lean against a housing of the receptacle. In another embodiment, an optical connector module comprises the mounting structure and the optical connector receptacle.