Well-aligned hexagonal ZnO nanotubes (NTs) arrays were synthesized on pretreated indium fin oxide (ITO) substrates by a simple hydro-thermal method. The morphology and structure of the products were characterized by scanning electron microscopy (SEM) and X-my dif-fraction analysis (XRD). A new method of substrate pretreatment was introduced to prepare ZnO coated films. The size of ZnO seeds and the formation rote of ZnO NTs were investigated. Further, the mechanism of the preparation of ZnO NTs was discussed. The photoluminescence (PL) spectrum measurement shows fairly intal defects existing in ZnO nanotubes.