The invention discloses a noiseless aluminum alloy section cutting device. The noiseless aluminum alloy section cutting device comprises supporting columns, a sound insulation layer, a fixed clampingdevice, a front cover, a soundproof box, a rear cover, a first servo motor, a chain, a fragment box, a rotary shaft, a fixed block, a saw blade, rocking bars, moving plates, bases, grooves, fixed baffles, a rectangular hole, a lead screw, workbench slide rails, second servo motors, driving shafts, nut seats, bearings and a workbench. The four supporting columns are arranged at the four corners ofthe lower portion of the workbench. The fixed block is arranged below the workbench. One side of the fixed block is connected with one end of the rotary shaft. The saw blade is welded to the other endof the rotary shaft. A gear is arranged on the position, between the saw blade and the fixed block, of the rotary shaft. The first servo motor is arranged on one side of the fixed block. The output end of the first servo motor is connected with the gear on the rotary shaft through the chain. The sound insulation layer is arranged on the lower portion of the workbench. The fragment box is arrangedbelow the sound insulation layer. The soundproof box is arranged on the workbench.