At present, value-taking of existing models of ship domain depends on the measured data or experimental data and it is lack of theory about quantitative study. According to the channel condition and ship characteristics of the lower Yangtze River, based on the concept of stopping sight distance to traffic engineering, we propose the concept of stopping sight distance to waterway engineering, analyze the braking accelerations of ship, and discuss the value of major axis about ship domain. The result indicates that that ship domain to waterway engineering is composed of reaction distance, breaking distance and safe distance. When the braking acceleration of the ship behind is three or four times as much as the ship ahead, the value of major axis about ship domain is 2.9 to 3.8 times of the ship length. The results is basically anastigmatic with the recommended values.