A switch assembly comprising: a housing including a handle; a main control switch comprising a body portion and a telescopic arm connected to the body portion and accommodated in an accommodating groove in the housing; a trigger switch positioned at the bottom of the handle and partly protruding out of the handle, and comprising a contact portion accommodated in the housing and located above the telescopic arm and a holding portion exposed below the housing, wherein the holding portion comprises a first side wall and a second side wall and an accommodating cavity positioned there in between; and a locking switch positioned at the top of the handle, opposite the trigger switch, and partly protruding out of the handle and comprising a pressing portion exposed above the housing and an abutting portion configured to interact with the holding portion of the trigger switch into either a locking position or a releasing position, in which locking position of the locking switch, the abutting portion is able to abut against the top of the second side wall of the holding portion to limit the action of the trigger switch, the trigger switch is in a locked state, and the main control switch cannot be started, and in which releasing position of the locking switch, the abutting portion is offset to the side of the holding portion, the locking switch and the trigger switch are releasable from abutting and the trigger switch is in a releasable state, in which state, if the holding portion is gripped, the telescopic arm of the main control switch is pressable downwards through the contact portion to enable the main control switch to be started. a housing including a handle; a main control switch comprising a body portion and a telescopic arm connected to the body portion and accommodated in an accommodating groove in the housing; a trigger switch positioned at the bottom of the handle and partly protruding out of the handle, and comprising a contact portion accommodated in the housing and located above the telescopic arm and a holding portion exposed below the housing, wherein the holding portion comprises a first side wall and a second side wall and an accommodating cavity positioned there in between; and a locking switch positioned at the top of the handle, opposite the trigger switch, and partly protruding out of the handle and comprising a pressing portion exposed above the housing and an abutting portion configured to interact with the holding portion of the trigger switch into either a locking position or a releasing position, in which locking position of the locking switch, the abutting portion is able to abut against the top of the second side wall of the holding portion to limit the action of the trigger switch, the trigger switch is in a locked state, and the main control switch cannot be started, and in which releasing position of the locking switch, the abutting portion is offset to the side of the holding portion, the locking switch and the trigger switch are releasable from abutting and the trigger switch is in a releasable state, in which state, if the holding portion is gripped, the telescopic arm of the main control switch is pressable downwards through the contact portion to enable the main control switch to be started.