The invention provides a connecting piece, a unit partition wall connecting structure and a connecting method of the unit partition wall connecting structure. The connecting piece comprises a connecting plate, wherein a notch is formed in the middle of the first end of the connecting plate; symmetrical bayonets are formed in both sides of the first end of the connecting plate; the length of the notch is larger than the width of the bayonets; and the width at the intersection of a center line of the notch and center lines of the bayonets is greater than or equal to 2 times of the depth of the bayonets; and the connecting piece is any one of a Z-shaped structure, an H-shaped structure and an I-shaped structure. The connecting piece enables the connecting plate to have a certain elastic reaction force through the arrangement of the notch, can be used for being connected with a partition wall unit in a clamped mode in the unit partition wall connecting structure and is convenient and firmto install and convenient to disassemble. The unit partition wall connecting structure cannot generate pollution and waste of materials, can be removed and displaced and can be reused, and resources are saved; and the connecting method is convenient to operate and quick to install.