The invention discloses a tape feeding mechanism for an automatic Teflon tape winding machine. The tape feeding mechanism comprises a base, the front face of the base is provided with a Teflon tape groove, the front end of the base is provided with a discharge outlet, and the discharge outlet communicates with the Teflon tape groove; the front end of the discharge outlet is further provided with a feeding device, and the feeding device comprises a driving unit, a tape feeding base and a tape feeding device; the tape feeding base is installed on the upper portion of the tape feeding device, the tape feeding base and the tape feeding device are both detachably connected with the base, a three-jaw sliding block is installed at the lower end of the base, and a shearing device is installed on the front face of the three-jaw sliding block. According to the tape feeding mechanism for the automatic Teflon tape winding machine, the feeding device is additionally arranged on the base, and conveying of Teflon tape is completed through the feeding device; due to the fact that the driving unit only needs to drive the tape feeding device to move, action of the driving unit is more accurate and stable, and efficiency is higher. Meanwhile, when Teflon tape with different specifications needs to be replaced, the effect can be achieved by only disassembling and assembling the tape feeding device, and the operating efficiency of equipment is improved.