Dust collecting barrel of sewing machine and working steps thereof

Provided is a dust collecting barrel of a sewing machine. The dust collecting barrel comprises a sewing machine, a controller arranged on the sewing machine and a barrel body. An opening is arranged in the upper end of the barrel body. A barrel cover covers the opening of the barrel body. A protection cover is fixedly installed on the barrel cover. A brushless motor is erected in the protection cover. A control system is connected to the brushless motor, a switch and a speed adjusting knob. A wind blade is connected to the brushless motor and arranged in the barrel body. A filtering core covers the wind blade. A handle is arranged on the protection cover. Multiple air discharging openings are arranged in the protection cover. A cloth sucking mouth, a first line sucking mouth and a second line sucking mouth are arranged in the barrel cover, and are communicated with interior space of the barrel body. The control system is connected with a plug. The dust collecting barrel is capable of collecting dust without cooperation of an external air source, so a problem of high noise during dust collection is avoided and the dust collecting device is applicable more widely.