The invention relates to a vortex-induced vibration restraining device and method for driving a rotating rod to rotate through detour flow allocation. The vortex-induced vibration restraining device is composed of three parts of a rotating part, a flow guiding cover shell and a transmission system. The rotating part is composed of a T-shaped sliding groove and a T-shaped sliding buckle with a supporting rod, and takes charge of rotating of the whole device. The flow guide cover shell is composed of a trepanning flow guiding cover and a direction adjusting tail plate. The transmission system iscomposed of two pairs of transmission rotating rods and matched transmission screw rods, gears, bearing seats and connection rods. Under the joint effect of flow rate allocation at an inflow port ofthe trepanning flow guiding cover of the vortex-induced vibration restraining device, rotating and shearing of a driven rotating rod, jet flowing at an outflow port of the trepanning flow guiding cover and dividing of a wake flow area by the direction adjusting tail plate, the total flow rate of external detour flow is decreased, the separation point of a detour flow boundary layer is delayed, theformed length of vortex is lengthened, and the width of wake is smaller, and thus vortex-induced vibration restraining without energy consumption is achieved.