The invention discloses a working method of an automatic noiseless mowing machine. The mowing machine comprises a mowing machine body, and a cutting mechanism, a driving mechanism, a grass recycling mechanism and a control device are arranged on the mowing machine body. A compression device is arranged in the grass recycling mechanism, the input end and the output end of the driving mechanism areconnected with the cutting mechanism respectively, and the grass recycling mechanism is arranged behind the cutting mechanism; the cutting mechanism, the driving mechanism, the grass recycling mechanism and the compression device are all connected with the control device. According to the working method of the automatic noiseless mowing machine, the grass recycling mechanism is arranged to recyclecut grass and well solves the problem of difficult recycling of smashed grass, and the compression device is arranged to compress recycled grass, so that the occupied space of grass is reduced, the time for taking out grass is saved, the working efficiency is improved, and accordingly the automatic noiseless mowing machine can better meet requirements of workers.