In this study, the use of plastic optical fiber(POF) was presented as a light guide in photocatalysis. To do so a simple method to remove the clad of POF was established and the most effective parameters on photocatalysis were investigated when used in a form of bundled array. Photocatalytic degradation of trichloroethylene(C2HCl3, TCE) and ethanol in the gasphase was also performed by using TiO2-coated plastic optical fiber reactor. Among 13 solvents with different solubility parameters and working groups, acetone was used to remove clad layer chemically, resulting in that optimized time of POF in acetone was selected 3 min to remove the clad layer completely. The photocatalytic activities of TiO2-coated optical fiber reactor system was dependent on the coating thickness, diameter and total clad-stripped surface area of POF. In ethanol degradation, in-situ FTIR measurement resulted in complete mineralization into CO2.