Abstract: On the basis of comparability of structure and constitute about sepiolite and basalt fibers, basalt was mixed with sepiolite in different proportions. Modified basalt fibers were made by melting,drawing the mixture and other processes using the ACC- Ⅱ high-temperature pot resistance furnace. The microstructure, morphology and characteristic of modified basalt fibers with basalt fibers were investigated by using Scanning Electron Microscopy(SEM).The influence of sepiolite on performance of basalt fibers was studied. The possible mechanism of the modification was discussed. The results show that a kind of modified basalt composites with new network structure can be produced by melting the mixture of sepiolite in the mass fraction of 10%~20% sepiolite. It was found that sepiolite can change the structure,constitute and performances of basalt fibers and improve the chemical permanence, flexibility and heat-resistant performance of basalt fibers.