The invention relates to a water plant crushing boat comprising a boat body, a push mechanism, and a crusher arranged on the boat prow; the crusher comprises side racks respectively positioned on two sides of the boat body and capable of rotatably connected relative to the boat prow; the crusher also comprises the following structures: a rotary shaft transversely arranged between the two side racks and capable of rotating around a self axis; a plurality of saw discs and parting cutters respectively arranged on the rotary shaft and capable of segmenting and crushing the water plant on the water surface; a motor driving the rotary shaft to rotate; a driving mechanism driving the two side racks to rotate relative to the boat prow, wherein the parting cutters are uniformly arranged between every two saw discs. The crushing boat can segment the water plant, and then cut and crush the water plant, is high in crushing efficiency, good in effect, novel and simple in structure, and low in cost.