A calculation method of limit load, deformation and energy dissipating of a ring net panel of a flexible protection net, includes step (1): determining geometrical parameters of the ring net, connection type of steel rings, and diameter of steel wires; step (2): determining a loading rate, a loaded region and a boundary condition of the ring net panel; step (3): obtaining basic mechanical parameters of materials through tests, and establishing a critical damage criterion of the ring net panel; step (4): establishing an equivalent calculation model of a ring net panel based on a fiber-spring unit; and step (5): calculating a puncturing displacement, a puncturing load and energy dissipating of the ring net panel. The method adopts a calculation assumption of load path equivalence.