A simple detachable illumination lamp tube includes a tube unit, a heat-dissipating unit, a light-emitting unit, a support unit and a lateral cover unit. The tube unit has a light-permitting hollow tube. The heat-dissipating unit has a heat-dissipating substrate received in the light-permitting hollow tube. The heat-dissipating substrate has two opposite lateral sides contacting the inner surface of the light-permitting hollow tube. The light-emitting unit has a plurality of strip light-emitting modules received in the light-permitting hollow tube. The strip light-emitting modules are disposed on the heat-dissipating substrate and electrically connected in sequence. The support unit has a plurality of support elements received in the light-permitting hollow tube and disposed between a bottom side of the heat-dissipating substrate and the inner surface of the light-permitting hollow tube. The lateral cover unit has two lateral covers installed on two ends of the light-permitting hollow tube.