In　the　event　of　a　flood,　the　choice　of　evacuation　routes　is　vital　for　personnel　security.　This　is　particularly　true　when　road　factors　play　an　important　role　in　evacuation　time.　In　this　study,　the　traditional　Dijkstra　algorithm　for　route　planning　is　improved,　and　the　evacuation　model　is　improved　from　2D　to　3D.　At　the　same　time,　the　Lasso　regression　method　is　adopted　to　take　the　road　factors　into　account　in　the　pedestrian　speed,　and　the　location　of　shelter　is　selected　and　optimized　through　the　calculation　results,　and　then　based　on　the　improved　3D　Dijkstra＇s　algorithm,　an　optimal　evacuation　route　method　in　different　flood　disasters　risk　levels　is　proposed,　which　can　make　pedestrians　reach　the　shelters　within　the　shortest　time.　After　taking　into　account　road　factors　(road　width,　slope,　non-motorized　lane　width,　and　pedestrian　density),　through　the　calculation　of　the　pedestrian　speed　formula,　the　estimated　evacuation　time　of　pedestrians　is　obtained.　By　combining　available　shelters　with　evacuation　routes,　the　optimized　algorithm　improves　the　evacuation　efficiency　facing　different　risk　levels　of　flood　disasters.　The　results　show　that　when　residents　are　confronted　with　flood　disasters　of　once-in-20-year,　once-in-50-year,　and　once-in-100-year,　the　proposed　optimization　algorithm　can　save　7.59%,　11.78%,　and　17.78%　of　the　evacuation　time.　Finally,　according　to　the　verification　of　the　actual　effect　in　Meishan　Town,　the　proposed　method　of　optimal　evacuation　route　planning　can　effectively　reduce　the　evacuation　time　of　pedestrians,　evaluate,　and　optimize　the　location　of　existing　shelter,　and　provide　suggestions　for　urban　road　reconstruction.