Xonotlite nanofibers were synthesized under hydrothermal condition by controlling reaction time and the temperature combined with cationic surfactant as templates. The result showed that long reaction time and low reaction temperature favored the formation of xonotlite nanofibers. The nanofibers obtained at 180 degrees C for 30 h in the presence of cationic surfactant have high aspect ratios more than 100 with diameters of 50-200 nm. The formation mechanism of xonotlite nanofibers was assumed to be a template-based synthesis and cationic surfactants could be used as templates. The evaluation of bioactivity revealed that bonelike apatite could be formed on the surface of xonotlite nanofibers after soaking in simulated body fluid (SBF) for 7 days and xonotlite nanofibers could be potential candidate as reinforcement reagents for preparation of bioactive composites.