The catalyst nanosized TiO2 was synthesized in the EbCDAB/ n-hexanol / water microemulsion .The structure and surface morphology was characterized by TG, XRD, FI-TR, and TEM methods. The photocatalytic degradation of methyl orange was used as a probe reaction to evaluate their photocatalytic activities using UV-light irradiation comparing with P25.The results indicated that compared with TiO2 synthesized in the CTAB microemulsion, these samples possessed smaller particle size, higher thermal stability and crystal stability. It was also found that the anatase phase can be maintained quite well even after calcination at 700 ℃.In additional，the photocatalytic activities for these samples had better photoactivity than P25.The smallest size particles and the highest photocatalytic activity was obtained when the mass ratio of n-hexanol to EbCDAB was 6:3．Under optimum condition, 82.6% decolorization of methyl orange could be achieved within 60 min UV irradiation.