Abstract: Taking alkali-resistant glass fibers (ARGF) as the research object, alkali-free, medium-alkali glass fibers and basalt fibers were selected as controls, mechanical property tests, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) elemental analysis, etc. were employed to explore the changes in mechanical characteristics, microscopic morphology and elemental content characteristics of the fibers after alkali erosion.The mechanism of action of ZrO₂ on alkali resistance was revealed.The results show that after erosion with NaOH solution for 6 hours, the strength retention rate of alkali-resistant glass fibers is 61.81%, significantly higher than that of medium-alkali (40.10%) and alkali-free glass fibers (16.40%), and with the extension of erosion time, its strength retention rate is slightly higher than that of basalt fibers.The dense protective layer formed by ZrO₂ during the alkali erosion process can effectively prevent the penetration of alkali solutions.Alkali-resistant glass fiber added to concrete, with the good alkali resistance provided by ZrO₂, has a promising application prospect.