The invention relates to a lock chamber energy dissipating open ditch of a ship lock, which belongs to the technical field of ship lock hydraulic buildings. The lock chamber energy dissipating open ditch of a ship lock comprises open ditches, wherein the open ditches are arranged outside a lock chamber gallery water outlet branch hole in a lock chamber of the ship lock and enclosed by force dissipating sills which are mutually spaced; one side of the water outlet branch hole is provided with at least two open ditches; and the force dissipating sills are provided with a water permeating hole or distributed into a step shape from a low part to a high part from the water outlet branch hole to the outer side. Compared with a single open ditch of the lock chamber of the traditional ship lock, the lock chamber energy dissipating open ditches of a ship lock can increase the energy dissipating volume for flowing out of the lock chamber gallery water outlet branch hole manifold and reduce the water flow turbulence and high local water surface in the lock chamber, thereby improving the energy dissipating efficiency and the safety of the ship to be locked in the lock chamber manifold, reducing the quantity of lock chamber galleries, simplifying the lock chamber structure, and reducing the engineering investment.