Abstract: With Zn(NO₃)₂·6H₂O, hexamethylenetetramine and polyethyleneimine (PEI) as raw materials, ZnO nanowires were synthesized on indium tin oxide conductive glass substrate by chemical bath deposition; the substrate was pre-deposited a ZnO seed layer. The deposition temperature of seed layer (150, 200 ℃), PEI concentration (0-9.0 mmol·L^-1), growth time (3-12 h) and water bath temperature (65-95 ℃) on morphology and size of the ZnO nanowires were studied. The results show that ZnO nanowires were successfully prepared with all the experimental parameters. When the seed layer deposition temperature was 200 ℃, the growth time was 9 h, the water bath temperature was 95 ℃, and the PEI concentration was 4.5 mmol·L^-1, the ZnO nanowires grew in regular hexagonal wurtzite structure, and arranged vertically on the substrate; the nanowires had the largest aspect ratio of 20.56.