The NiO thin film was deposited on the stainless steel substrate by spin-coating compared with thermal treatment technique. Thermal decomposition behavior of gel precursor, the structure, morphology and electrochemical properties of NiO thin film were characterized by thermogravimetric/differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and constant current charge-discharge techniques. The results show that the stable sol is synthesized by nickel acetate and PAA. The gel precursor completely decomposes and gradually forms the nanocrystalline NiO at 450°C during the sintering. The crystal structure of NiO films become more integrity and particles large with the increasing of sintering temperature. The morphology and structure of the NiO thin film sintered at 500°C for 2h is perfect and exhibits high discharge specific capacity and well cycle performance whose initial and stable discharge capacity after 20 cycles are 1147.5mAh/g and 741mAh/g , respectively.