TiO2 membranes were prepared on porous Ti supports through the in situ oxidation method. The effects of oxygen concentration, oxidation temperature, and oxidation time on the thickness, pore size, and microstructure of the prepared TiO2 membrane were investigated. The results showed that with increasing oxygen concentration, oxidation temperature, and oxidation time, the thickness of the prepared TiO2 membrane gradually increased, and the pore diameter gradually decreased. The optimum preparation conditions were—oxygen concentration was N2:O2 = 2:1, oxidation temperature was 800 ℃, and oxidation time was 60 min. The prepared TiO2/Ti composite membranes had a flat and smooth surface, uniform thickness, and only a rutile TiO2 characteristic peak formed on the surface of the membrane. The prepared TiO2/Ti composite membrane had a narrow pore size distribution, and the average pore size was about 0.312 μm. In addition, the prepared TiO2/Ti composite membranes showed an excellent stability.