Carbon-based materials are currently used for anodes in commercial lithium ion secondary batteries. The theoretical capacity for carbon is only 372mAh/g, and new materials are being developed for anodes to raise the electrical capacity and cycling times. One of the most promising materials is tin oxide that has 50% more electrical capacity and has been studied extensively in the industrial and academic institutions. While most studies have been concentrated on the electrochemical behavior in the charge-discharge process, microstructure evolution along with phase transformation have been emphasized in this work. Tin oxide films are deposited on stainless steel substrate by sputtering and spray. A cell consists of a pure lithium foil as anode and tin oxide film as cathode along with 1M LiClO4 in DMC/EC mixture as electrolyte is fabricated and employed in the charge-discharge test and Cyclic Voltammetry. In the charge-discharge test, we use a constant current of 0.09mA to charge or discharge to the voltage that we need. In the Cyclic Voltammetry test, we change the scanning rate and scanning range. Microstructures developed and phase transformation in different stages of the charge-discharge or CV test process are examined by XRD, SEM and TEM.