Linjiaba hydro junction is located at the west waterway on Beijing—Hangzhou Grand Canal in north Jiangsu.In order to meet the demand of cargo forecasts,it’s necessary to construct the second line ship lock.The general layout of the second line ship lock is researched,including the width of sharing approach channel,the type of approach channel of the second line ship lock,the construction condition,the chamber structure of the first line ship lock,the site’s topographic condition,etc.Different distances between axes of the first line and the second line are discussed and a distance of 70 m between axes of the two locks is determined according to general demonstration.At last,some optimized suggestions are presented to improve the design.