An optical fiber joint, comprising: an optical cable; an insertion core sleeved onto the optical cable; a connecting piece sleeved onto the insertion core, wherein the optical cable passes through the insertion core, the insertion core including oppositely arranged first and second ends (150a, 150b), and the optical cable is exposed at the first end of the insertion core far from the connecting piece, the connecting piece sleeved on the second end of the insertion core; an inner sleeve element with a cavity inside, wherein an optical fiber extending out of the optical cable is held in the cavity, one end of the inner sleeve element is fixed at the optical cable, and a sleeve is placed at the other end of the inner sleeve element, wherein the inner sleeve element extends along an axial direction of the insertion core, where the first end of the insertion core far from the connecting piece is held in the inner sleeve element; and an outer sleeve element sleeved onto the connecting piece and the insertion core, wherein the outer sleeve element sleeved onto an outer side of the inner sleeve element, and the outer sleeve element is capable of axially rotating around the sleeve; wherein the sleeve of the inner sleeve element at least partially protrudes out of the outer sleeve element, and a tail end of the sleeve protruding out of the outer sleeve element has an opening, so that the tail end of the sleeve forms a C-shaped section; wherein one end of the connecting piece has a shaft shoulder, an elastic component sleeved onto the connecting piece, wherein the shaft shoulder is configured to abut against an end of the elastic component; wherein an end of the outer sleeve element is slidingly connected to the connecting piece, and inwardly forms a flange that abuts against the other end of the elastic component, wherein the elastic component is clamped between the flange and the shaft shoulder and is configured to provide elasticity against the insertion core for the outer sleeve element for preventing a loose connection, wherein the opening of the C-shaped tail end of the sleeve is horn-shaped; wherein an external end of the outer sleeve element has an arrow alignment identifier for indicating connection and disconnection states. an optical cable; an insertion core sleeved onto the optical cable; a connecting piece sleeved onto the insertion core, wherein the optical cable passes through the insertion core, the insertion core including oppositely arranged first and second ends (150a, 150b), and the optical cable is exposed at the first end of the insertion core far from the connecting piece, the connecting piece sleeved on the second end of the insertion core; an inner sleeve element with a cavity inside, wherein an optical fiber extending out of the optical cable is held in the cavity, one end of the inner sleeve element is fixed at the optical cable, and a sleeve is placed at the other end of the inner sleeve element, wherein the inner sleeve element extends along an axial direction of the insertion core, where the first end of the insertion core far from the connecting piece is held in the inner sleeve element; and an outer sleeve element sleeved onto the connecting piece and the insertion core, wherein the outer sleeve element sleeved onto an outer side of the inner sleeve element, and the outer sleeve element is capable of axially rotating around the sleeve; wherein the sleeve of the inner sleeve element at least partially protrudes out of the outer sleeve element, and a tail end of the sleeve protruding out of the outer sleeve element has an opening, so that the tail end of the sleeve forms a C-shaped section; wherein one end of the connecting piece has a shaft shoulder, an elastic component sleeved onto the connecting piece, wherein the shaft shoulder is configured to abut against an end of the elastic component; wherein an end of the outer sleeve element is slidingly connected to the connecting piece, and inwardly forms a flange that abuts against the other end of the elastic component, wherein the elastic component is clamped between the flange and the shaft shoulder and is configured to provide elasticity against the insertion core for the outer sleeve element for preventing a loose connection, wherein the opening of the C-shaped tail end of the sleeve is horn-shaped; wherein an external end of the outer sleeve element has an arrow alignment identifier for indicating connection and disconnection states.