An adjustable table leg which includes an inner lead screw linking an inner lead screw nut to move an outer lead screw nut along an outer lead screw, so that the inner lead screw nut drives a lead screw outer pipe to link a leg middle pipe and the outer lead screw nut to drive a lead screw inner pipe to move an leg outer pipe up and down synchronously. Therefore, the upward and downward transmission is more stable, the upward and downward adjustment is smoother, the phenomenon of jamming does not occur, the adjustment precision is higher, the stress of the inner lead screw nut and the outer lead screw nut is more uniform, the fatigue degree is reduced, and the service life is increased.