In this study, interface models of different polymer fibers and geopolymer products were constructed and the microscopic action mechanisms behind different polar oxygen-containing functional groups were revealed by analyzing the static structure of the interface and fiber pull-out process. The results show that, compared with polypropylene (PP) fibers, there is a strong hydrogen bond interaction in polyvinyl alcohol (PVA) and polyacrylic acid (PAA) fibers, respectively. After reaching equilibrium, the interlayer spacing of PVA and PAA fibers becomes smaller. At the interface, there are both ionic bonds and hydrogen-bonding connections, and the stability of ionic bonds is greater than that of hydrogen bonds. As the loading rate increases, the shear strength shows an increasing trend. Since the carboxyl of PAA fibers has stronger polarity than the hydroxyl of PVA fibers, the end deformation of the matrix is greater. During the pull-out process, the influence of the loading rate is greater than the anchoring effect of hydroxyl in PVA fibers but lower than that of carboxyl in PAA fibers.