The rutile phase of TiO2 forms a stable phase at high temperatures compared to anatase phase, but the stable temperature range of anatase changes depending on the synthesis conditions. In this study, nano-sized TiO2 was synthesized by the Sol-gel method using TiOSO4 and a mixed solvent of ethanol and distilled water, and the phase change of anatase and rutile according to pH and heat treatment temperature was investigated. Changes in the ratio of anatase and rutile wereobserved by changing the pH (3, 5, 7, 9) and heat treatment temperature (500, 600, 700, 800, 900°C) conditions of the prepared TiO2. As a result of observing these changes through XRD and FE-SEM analysis, anatase TiO2 at 500°C and rutile TiO2 at 900°C were observed. According to the pH, at these intermediate temperatures of 600, 700 and 800°C, the ratio of anatase and rutile changes. At 700°C, it was concluded that pH = 3~5 had a larger ratio of anatase TiO2, andpH = 7~9 had a larger ratio of rutile TiO2.