A receptacle structure for optical sub-assembly for transceivers includes: a receiving tube; a base seat coaxially disposed in the receiving tube, the base seat having a first fiber stub receiving hole and a second fiber stub oblique receiving hole; a sleeve coaxially disposed in the base seat and the receiving tube; a first fiber stub coaxially disposed in the first fiber stub receiving hole of the base seat and the receiving tube; a second fiber stub connected in the second fiber stub oblique receiving hole of the base seat; and an optical fiber installed between the first and second fiber stubs. The second fiber stub is disposed in the base seat in an inclined state, whereby the coupling loss is reduced and the optical coupling efficiency is increased.