In recent years,Mazu waterway of Madang reach appears new changes,and the waterway maintenance turns increasingly difficult.The primary cause of such issue is summarized as turbulence at the upstream reach,and shallow depth at downstream.Based on the experimental investigation to the reason why the Mazu waterway results in an obstruction,12 programmes are studied in fixed-bed models and 6 programmes are studied in movable-bed models,and determines at last the recommended engineering scheme.After implementation of the project during 2009 and 2010，the waterway condition is improved obviously.