Underwater sludge sampling device

The underwater sludge sampling device comprises a sampling pipe and an operating rod, a mounting seat for mounting the operating rod is arranged at the upper end of the sampling pipe, and the sampling pipe is arranged in a vertically-through manner; the operating rod comprises a rod body, a piston piece and a handpiece, the piston piece is arranged at the lower end of the rod body, and the handpiece is arranged at the upper end of the rod body; the mounting seat comprises a seat body and a mounting plate, the seat body is connected with the upper end of the sampling tube, the mounting plate is arranged at the upper end of the seat body and spaced from the seat body, and a ventilation part is formed between the mounting plate and the seat body; a first threaded hole is formed in the mounting plate, the rod body is provided with a threaded part at the upper part of the piston piece, and the rod body is in threaded connection with the first threaded hole through the threaded part; the lower end of the sampling p