The invention relates to a structure for realizing four-path optical transmission. The structure comprises a connecting plug, a shell sleeved in the connecting plug and an inner core sleeved in the shell, wherein the inner core is internally provided with an inner core upper cover, an inner core middle cover and an inner core lower cover; the inner core middle cover is positioned between the inner core upper cover and the inner core lower cover; a PCBA module is further arranged in the inner core; two TOSAs and two ROSAs are further arranged in the inner core; the two TOSAs and the two ROSAs are connected with the PCBA module; the connecting plug and the inner core are respectively provided with four-path ports; four inserting core terminals of the connecting plug are respectively inserted into the ports of the TOSAs and the ROSAs; the TOSAs and the ROSAs are respectively arranged to be SC interfaces; the inserting cores of the TOSAs and the ROSAs are single-mode inserting cores; and the four terminals of the connecting plug are the single-mode inserting cores simultaneously. According to the structure provided by the invention, the volume is small; the density is high; the optical power is stable in the docking process; and the reliability is stable.