Abstract: A brush-less chainsaw is disclosed, comprising a housing, a brush-less motor, a transmission device, a power supply, an electronic commutator, a brake backplate, a chain plate, and a chain. The brush-less motor, the transmission device, and the electronic commutator are disposed in the housing. The brush-less motor is connected with the electronic commutator. A power output end of the brush-less motor is connected with the transmission device. The electronic commutator detects a position signal of the brush-less motor and controls the brush-less motor to drive the chain and the chain plate to rotate. The electronic commutator receives a brake signal from the brake backplate and transmits the signal to the brush-less motor. The brush-less motor drives the chain to brake according to the brake signal. The brush-less chainsaw has the advantage of optimizing the performance, along with small size, low cost, large torque, and small braking current.