A scissor jack comprises a support member coupled to a first upper arm and a second upper arm; a base coupled to a first lower arm and a second lower arm; a first connector pivotally connected to the first upper arm and the first lower arm; a second connector pivotally connected to the second upper arm and the second lower arm; a lead screw fixed to the first connector; and a driving member having a first through-hole. The driving member is rotatable connected in the second connector and the lead screw is connected with the first through-hole via thread connection.