An immersion tube for RH vacuum refining furnace is characterized in that the main body of the immersion tube is a straight cylindrical steel shell; The lower part and the outer side of the steel shell are both provided with refractory castables, and the inner side of the steel shell is provided with refractory materials; The steel shell wall 10 ～ 15cm away from the upper end surface of the outer castable is provided with multilayer round holes; A screw rod with a diameter smaller than the diameter of the round hole is placed in the round hole; One end of the screw is located in the round hole, and the other end is penetrated through the round hole. The screw is fixed on the inner and outer sides of the steel shell through a nut; The steel wire mesh is arranged on the screw outside the steel shell.