Changzhou 3rd and 4th lane locks are the biggest single-step locks in China.Based on the parallel layout plan for these new locks,the filling and emptying system with single long culvert in the lock wall and lateral manifolds in the lock bottom has been put forward.By means of hydraulic analysis and model test (model scale 1〖KG-*2/3〗32),the specific layout of the filling and emptying system and the valve’s opening patterns under different operation mode have been determined,the hydraulic characteristics during lock filling and emptying have also been studied,the uneven flow distribution in lock chamber with single wall culvert layout has been well improved.The results indicate that the layout of the filling and emptying system is reasonable and practical;each of the hydraulic characteristics satisfies the designing requirements.The filling and emptying system which is laid out between the two locks is convenience for management and can reduce the work quantities,it also can save water due to the connecting culvert.The results can be used for the huge lock design and lock water saving study.