The effect of ion irradiation on ZnO thin film's crystal orientation during dual ion beam sputtering deposition is studied. Glass and Si substrates are irradiated during depostion by oxygen and argon ions. The irradiating oxygen ions are swept away from the substrate by a cross-electric field to examine the effect of high energy neutral atoms on crystal orientation. Argon and oxygen positive ions prepared in a saddle field ion gun can effectively form c-axis orientation in ZnO film deposition. But oxygen high energy neutral atoms tend to deform the c-axis orientation of the films. ZnO film prepared by this method is useful in the production of devices with good piezoelectric and pyroelectric properties.