The invention discloses a structure and method for regulating diffusion flowing of a pump station forebay, and belongs to the technical field of water conservancy projects. The structure comprises anapproach channel, the forebay, water inlet ponds, separating piers between the water inlet ponds and water pump water sucking pipes in the water inlet ponds and is characterized in that the forebay isprovided with a plurality of flow separating plates and an arc strip plate, the flow separating plates are fixed to the forebay, and are in one-to-one corresponding to the separating piers, the arc strip plate is fixed to the rear ends of the flow separating plates, and the flow separating plates are connected into a comb-shaped combination plate. The structure is suitable for forward water inletforebays of various pump stations. The forebay flowing state can be effectively improved, the vortex and the backflow of the forebay can be removed, the water flow in the forebay and the water inletpond can be more smooth, the good water inlet condition is provided for water inlet of a water pump, the safe and economic operation of a pump station is facilitated, and the structure is simple, technically reliable, easy to implement, small in engineering amount, and large in economic benefit. The structure is technically reliable, easy to implement, obvious in benefit and wide in application prospect.