The paper investigates the effects of the topography, flow and revetment broken on Kaoping-bridge by using field survey data. Two causes are considered for the collapsed bridge. The remote cause was the gradually degrading bed of Kaoping river under over-mining. The immediate cause was the broken revetment due to impact of flow. It is concluded that there are two effects owing to Typhoon Bilis: scouring and deposition in this bridge. The primary factors causing the scouring include whirlpools at top of bridge, lift force, hydraulic jump, drop flow and rusted revetment. These factors will make the bridge dangerous. As for the deposition, the primary factors which causing it are effects of lateral flow and bridge screen.