The door water delivery is an important characteristic of triangular gate.Based on the door water delivery of triangular gate,the low water head ship lock may not be equipped with the valve to reduce the engineering construction cost,but it is still difficult to grasp the specific applicable conditions.Based on the Daliuxiang ship lock without a valve,by use of the method of combining the theoretical calculation with the site factual measurement,the water power and the opening and closing force under the door water delivery have been analyzed.The study shows that:the larger the entrance is,the smaller the water head of the triangular gate which can bear the door water delivery is;at present,the relevant calculation formulas for the door water delivery still need to be combined with the structural characteristics of the triangular gate to determine the flow coefficient;in addition to the calculation of standard formulas,the influence of the door body gap flow and inertia resistance moment shall be also considered by the opening and closing force of triangular gate.