Flow guide device and method for conducting framing construction on river channel through flow guide device

The invention discloses a flow guide device and a method for conducting framing construction on a river channel through the flow guide device. The flow guide device is of a double-U-shaped guiding structure and comprises an upper U-shaped reinforced concrete structure and a Larsen steel sheet pile, wherein an opening of the upper U-shaped reinforced concrete structure faces upwards, the Larsen steel sheet pile is arranged below a bottom plate of the upper U-shaped reinforced concrete structure, and is perpendicular to two side walls of the upper U-shaped reinforced concrete structure to form an inverted-U-shaped structure, a river channel is constructed in two stages, and the double-U-shaped flow guide structure is arranged above a constructed first-stage tunnel and serves as a water passing channel of a temporary river channel and a protection structure of the constructed first-stage tunnel in the second-stage construction period. The structure features are distinct, on the premise of normal navigation, floo