Polymethylmethacrylate-ZnO (PMMA-ZnO) fibrous anion exchanger was prepared by solid-gel method. The structure and morphology of the prepared fibrous anion exchanger were characterized by Fourier transform spectroscopy (FTIR), Field emission Scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Energy-dispersive X-ray (EDX) analysis. The dielectrical constants (e 0 , e″), dielectric loss (tand), and AC conductivity (r ac ) were studied as a function of frequency. The material was found to be highly desirable for electroanalytical application as anionic sensor; its membrane electrode has been developed for the detection of AsO À3 4 in solutions. The detection limit of AsO À3 4 selective membrane electrode is 1 9 10 À9 M to 1 9 10 À1 M with a response time of 35 s and its working pH range is 4-7. The selectivity coefficient values for interfering ions indicate good selectivity for arsenate (AsO À3 4 ) over interfering anions. The accuracy of the results was compared by Portable Coulometric Analyzer (PCA-Arsenomat).PMMA-ZnO anion exchanger 4 ions over other interfering ions.