The invention relates to a fixing device capable of precisely feeding a catheter during surgery and a working method thereof, and belongs to the field of medical instruments. The fixing device comprises a base, guiding holes are formed in the base, the guiding holes are internally matched with guiding rods, a shelf is fixed to the tops of the guiding rods, a lifting air bag is arranged between theshelf and the base and connected with a power air bag through an air guiding pipe, a one-way valve is arranged on the joint of the lifting air bag and the air guiding pipe, an air releasing valve isarranged on the lifting air bag, stopping blocks are fixed to the bottoms of the guiding rods, the guiding rods are sleeved with lifting springs, and the lifting springs are located between the stopping blocks and the base. By means of the fixing device, the catheter can be properly lifted up according to the surgical condition, so that air is prevented from entering a human body to cause air embolism; the catheter can be quantificationally and precisely fed according to the surgical condition, so that the surgical effect is guaranteed.