During the period of Republican China,Yongding River often flooded.During 38 years,It flooded 17 times,averaged about every 2 years,being one of the most dangerous river in the Beijing-Tianjin area.Beijing Government and Nanjing National Government paid much emphasis on it,making a series of programme,and taking some measures to harness it.In the harness process,some modern science and technology were used,a overall plan for treating it has been made,and some achievements had acquired.But,due to the political situation,the war occurred frequently,the harness on Yongding River had to be on and off.After the outbreak of the war to resistance against Japan,many projects on Yongding River had to be stopped.