Invasion by nonindigenous species has been recognized as second only to loss of habitat and landscape fragmentation as a threat to global biodiversity.Management and control of nonindigenous species is perhaps the biggest challenge that conservation biologists will face in the next few decades.Former studies showed high complex habitat increased the survival rate of aquatic animals.In this study,we used submerged plants(Hydrilla varticillata)as refuge of native species,Rhodeus sinensis,and conducted a series of laboratory experiments that established structural complexity and manipulated prey density to test in different prey density whether increase structural complexity could decrease the predation of nonindigenous species Procambarus clarkii.We found that in different prey density (low,middle,high),increased habitat complexity could decrease the predation of P.clarkii on R.sinensis.In addition,the number of R.sinensis preyed by P.clarkii was dependent on density prey,increased nonlinearly as density.The interaction between habitat complexity and density of R.sinensis has no significant effect on the number of R.sinensis preyed by P.clarkii.The results of our study indicate that we can increase structural complexity of water to decrease the predation of nonindigenous predator on native species and protect native species.