In order to investigate the content of hydrated PbO2 and its influence on lead acid batteries cycle life performance, PbO2 films with four typical α-PbO2/β-PbO2 ratios (pure α-PbO2, α-PbO2/β-PbO2 = 0.3, α-PbO2/β-PbO2 = 1, and pure β-PbO2) on gold or graphite substrates were characterized by X-ray diffraction, scanning electron microscopy, and electrochemical quartz crystal microbalance. The effects of electrodeposition parameters on the morphologies and crystal phases of electrodeposited PbO2 samples were investigated. The hydrated PbO2 contents of the four samples were determined by electrochemical quartz crystal microbalance. The samples with α-PbO2/β-PbO2 = 1 and 0.3 exhibited the smallest and the highest contents of hydrated PbO2 among the four samples. Samples with almost pure α-PbO2 and pure β-PbO2 exhibited similar amounts of hydrated PbO2. The PbO2 film electrode with initial α-PbO2/β-PbO2 = 1 was still stable after 750 cycles.