ZnO thin films on glass substrate were depostied by RF magnetron reactive sputter with various argon/oxygen gas ratios and substrate temperatures. Crystallinities, surface morphologies, chemical compositions, and electrical properties of the films were investigated by XRD, SEM, XPS and electrometer(keithley 617). All films showed a strong preferred orientation along the c-axis on glass substrate, and the chemical stoichiometry was obtained at Ar/O$_2$.=50/50. The propagation velocity of ZnO SAW filter was about 2,590 m/sec and insertion loss was a minimum value of abut -21dB.