Fishway outlet adapting to water level change and design method

The invention relates to a fishway outlet adapting to water level change and a design method. The fishway outlet comprises an overflow section; the overflow section is connected with an outlet section; the overflow section is formed by connecting multiple overflow pools having the same lengths and widths with conventional pools; fish passing facilities are respectively arranged between a fishway and the overflow section, between the overflow section and the outlet section, among all the conventional pools and all the overflow pools; the outlet section is as wide as the conventional pools; the height of a side wall of the outlet section is slightly higher than a highest value of a reservoir upstream water level change difference; and the bottoms of all the overflow pools at the outlet section and the overflow section are on the same horizontal line. The fishway outlet adopts the mode of arranging the overflow section and the outlet section in the fishway outlet to enable the continuously changed upstream reser