Abstract: In order to solve the application problems of TiO₂ such as the poor effective utilization rate for solar energy, high recombination rate of photoinduced electrons and holes, low photocatalytic activity and difficulty in recycle etc., nano Ag-carbon nanotube (CNT)-mixed crystal TiO₂ composite fibers were synthesized successfully by electrospinning technology, and the microstructures and constructions of the materials were analyzed in detail by characterization methods such as SEM, XRD, EDS and Raman etc., thus the photocatalytic activities of nano Ag-CNT-mixed crystal TiO₂ composite fibers for methylene blue were investigated. The results show that the mixed crystal of anatase- and rutile-TiO₂ can not only reduce the band gap, but also slow down the combination and cancellation of photoinduced electrons and holes. The localized surface plasmon resonance of Ag nanoparticles can enhance the light absorption of nano Ag-CNT-mixed crystal TiO₂ composite fibers, and CNT can promote the effective segregation of photoinduced electrons and holes. The degradation rate of nano Ag-CNT-mixed crystal TiO₂ composite fibers for methylene blue in the first cycle reaches 97.5%, and the degradation rate for methylene blue after 5 catalytic cycles still retains above 90.0%. The conclusions obtained show that the new type nano Ag-CNT-mixed crystal TiO₂ composite fiber prepared by electrospinning is a high-activity photocatalyst and is easy to be recycled, which has application prospects for the photo degradation of methylene blue.