A loose-leaf notebook and its binding structure are provided. The binding structure includes a base plate. The base plate is provided with binding strips and snapping holes corresponding to the binding strips. A bottom end of each of the binding strips is fixed on the base plate, and a top end of each of the binding strips is inserted into a corresponding snapping hole. Due to the elasticity of the material itself, hands will not be hurt during writing, and loose-leaf papers can be easily flipped. If a user needs to remove or change an order of the loose-leaf papers, the user can remove the binding strips from the snapping holes to easily change papers and perform rebinding. The binding structure can also be reused by replacing the loose-leaf papers of the loose-leaf notebook.