A connecting buckle, comprising: an upper cover (1.0) and a lower cover (2.0) disposed correspondingly, wherein U-shaped connecting grooves (1.1) are correspondingly formed in the head ends of the upper cover (1.0) and the lower cover (2.0) respectively, two first riveting shafts (3.0) are disposed on two sides of the connecting grooves (1.1), a second riveting shaft (4.0) and buckle ring installing grooves (1.2) are disposed at the tail ends of the upper cover (1.0) and the lower cover (2.0), a buckle ring fixing shaft (5.0) is disposed in the buckle ring installing grooves (2.0), a buckle ring (5.1) is disposed at the tail end of the buckle ring fixing shaft (5.0), a buckled cavity (6.0) is formed between the upper cover (1.0) and the lower cover (2.0), characterized in that the connecting buckle further comprises a return device (8.0), a rotating shaft (6.1), a locking device (7.0), and the return device (8.0) are disposed in the buckled cavity (6.0), and the locking device (7.0) and the return device (8.0) are disposed correspondingly; the locking device (7.0) comprises an upper locking tongue (7.1) and a lower locking tongue (7.2) disposed correspondingly, wherein the upper locking tongue (7.1) is provided with an upper locking groove (7.11) with an opening on the right side, an upper rotating hole (7.12) corresponding to the rotating shaft (6.1) is formed in the tail end of the upper locking tongue (7.1), an upper shift lug (7.13) is protrusively disposed on the left side of the upper locking tongue (7.1), the lower locking tongue (7.2) is provided with a lower locking groove (7.21) with an opening on the left side, a lower rotating hole (7.22) corresponding to the rotating shaft (6.1) is formed in the tail end of the lower locking tongue (7.2), a lower shift lug (7.23) is protrusively disposed on the right side of the lower locking tongue (7.2), a limit stopper (6.2) for blocking the upper shift lug (7.13) and the lower shift lug (7.23) are disposed at the bottom of the buckled cavity (6.0), a locking spring abutting against the tail ends of the upper locking tongue (7.1) and the lower locking tongue (7.2) is also disposed at the bottom of the buckled cavity (6.0), and a closed ring is formed between the connecting grooves (1.1) and the head ends of the upper locking tongue (7.1) and the lower locking tongue (7.2) due to an elastic force of the locking spring; and the return device (8.0) comprises an upper return tongue (8.1) and a lower return tongue (8.2) that are L-shaped and disposed correspondingly, wherein the head end of the upper return tongue (8.1) is hinged to the head end of the lower locking tongue (7.2), the head end of the lower return tongue (8.2) is hinged to the head end of the upper locking tongue (7.1), the tail ends of the upper return tongue (8.1) and the lower return tongue (8.2) are hinged to each other, and the upper return tongue (8.1) and the lower return tongue (8.2) are located on the outer side of the connecting grooves (1.1) due to the elastic force of the locking spring. the connecting buckle further comprises a return device (8.0), a rotating shaft (6.1), a locking device (7.0), and the return device (8.0) are disposed in the buckled cavity (6.0), and the locking device (7.0) and the return device (8.0) are disposed correspondingly; the locking device (7.0) comprises an upper locking tongue (7.1) and a lower locking tongue (7.2) disposed correspondingly, wherein the upper locking tongue (7.1) is provided with an upper locking groove (7.11) with an opening on the right side, an upper rotating hole (7.12) corresponding to the rotating shaft (6.1) is formed in the tail end of the upper locking tongue (7.1), an upper shift lug (7.13) is protrusively disposed on the left side of the upper locking tongue (7.1), the lower locking tongue (7.2) is provided with a lower locking groove (7.21) with an opening on the left side, a lower rotating hole (7.22) corresponding to the rotating shaft (6.1) is formed in the tail end of the lower locking tongue (7.2), a lower shift lug (7.23) is protrusively disposed on the right side of the lower locking tongue (7.2), a limit stopper (6.2) for blocking the upper shift lug (7.13) and the lower shift lug (7.23) are disposed at the bottom of the buckled cavity (6.0), a locking spring abutting against the tail ends of the upper locking tongue (7.1) and the lower locking tongue (7.2) is also disposed at the bottom of the buckled cavity (6.0), and a closed ring is formed between the connecting grooves (1.1) and the head ends of the upper locking tongue (7.1) and the lower locking tongue (7.2) due to an elastic force of the locking spring; and the return device (8.0) comprises an upper return tongue (8.1) and a lower return tongue (8.2) that are L-shaped and disposed correspondingly, wherein the head end of the upper return tongue (8.1) is hinged to the head end of the lower locking tongue (7.2), the head end of the lower return tongue (8.2) is hinged to the head end of the upper locking tongue (7.1), the tail ends of the upper return tongue (8.1) and the lower return tongue (8.2) are hinged to each other, and the upper return tongue (8.1) and the lower return tongue (8.2) are located on the outer side of the connecting grooves (1.1) due to the elastic force of the locking spring.