The invention discloses an adjustable type riverway sediment removing device for a trailing suction dredger and relates to the field of dredging equipment. The adjustable type riverway sediment removing device for the trailing suction dredger comprises a trailing shell and a moving hood. The moving hood comprises a connection shell body and a work shell body. One side edge of the connection shellbody is fixedly connected with one side edge of the work shell body. The connection shell body is located inside the trailing shell and rotationally connected with an opposite side wall of the trailing shell. The outer arc face of the top of the work shell is fixedly provided with a power mechanism. A crushing mechanism is installed in the work shell. The power mechanism drives the crushing mechanism to rotate through two groups of transmission mechanisms. The side edge, far away from the connection shell, of the work shell is evenly provided with a plurality of rake teeth. The side walls at the two ends of the work shell are symmetrically and fixedly provided with two lug plates. Each lug plate is internally provided with a straight groove opening. According to the adjustable type riverway sediment removing device for the trailing suction dredger, through the energy of water flow, the power mechanism is made to drive the crushing mechanism to rotate through the transmission mechanisms, so that dredged materials are crushed, the situations that the rake teeth are damaged, and a dredging pipe is blocked can be avoided, and the dredging efficiency of the trailing suction dredger is improved.