A multifunctional simple riverway survey device comprises a telescopic rod, the telescopic rod is formed by connecting a plurality of hollow rods in a sleeved mode, a transmission device is arranged on the lower portion of each hollow rod, each transmission device comprises a conveying belt idler wheel, and the conveying belt idler wheels are connected with the hollow rods through a frame. Scale indications of the total length are marked on the telescopic rod from the head rod to the tail rod, the tail rod is connected with a reel through a support, a nylon belt is wound on the reel, and a plurality of tooth-shaped protrusions are arranged on the side face of the nylon belt. The nylon belt is led out of the reel, penetrates through all the frames, then penetrates through the floating buckle and finally is connected with the weight falling piece. The device is simple in structure and low in manufacturing cost; the device is light in weight, small in size, convenient to carry and suitable for outdoor single-person measurement.