A self-locking connection device includes a housing, and a sliding block and a buckle, which are mounted in the housing. The sliding block slides back and forth along the housing and is locked in case that the sliding block is pushed to a front side, and is unlocked and reset in case that the sliding block is pushed to the front side again. An inclined wall for supporting the buckle is provided inside the housing, a height of the inclined wall gradually decreases from front to rear, the buckle is connected to the sliding block to move along the inclined wall with the sliding block, and the buckle is locked at a top end and protrudes out of the opening in case that the sliding block is locked at the front side.