Carbon fibers and basalt fibers were used to modify geopolymers. The impact of fiber content on the fluidity， mechanical properties， resistivity and piezoresistive behavior of geopolymers were analyzed. And then， the influence mechanism of fiber conductivity on the piezoresistive properties of geopolymers was clarified. The results show that carbon fibers have a greater impact on material fluidity of geopolymers than basalt fibers. When the carbon fiber content increases， the resistivity of geopolymers decreases significantly and the resistivity curves can be divided into slow-decreasing， sudden-decreasing and flat stages. With the increase of carbon fiber content， the effect of carbon fiber on the piezoresistive properties of geopolymers first enhances and then weakens. When the volume fraction of carbon fiber is 0.4%， the piezoresistive properties of geopolymers is optimal. However， the basalt fiber has a weakening effect on the piezoresistive properties of geopolymers.