The utility model relates to a fast replacing pliers head used in clamping tool, which comprises a left and right pliers heads, a locating shaft and a pliers head formed by connecting a connection board and a pin shaft, wherein, the corresponding insides of front ends of the left and right pliers heads are provided with concave cavities; the inside of each cavity is provided with a die. The utility model is characterized in that: the circumference of the die is provided with a gap, while the circumference of the upper port of the gap is provided with a concave stage. Meanwhile, the utility model has the advantages that: when the pliers head of clamping tool needs to replace die, user can just screw out part of the bolt positioned at the pliers head part so as to separate the screw cap arranged on the bolt from the concave stage and to take out the die through pushing in the bolt along the gap, thereby realizing replacement of die without completely screwing the bolt out from the threaded part of the pliers head; moreover, the design not only simplifies operation during replacing bolt and quickens replacement of die, but also improves efficiency of installation construction.