Micro-porous TiO2 ceramic films have been grown on titanium plates by the micro-plasma oxidation method with the electrolyte of H2SO4. The influence of La3+ ion addition in the electrolyte on the photo-catalytic activities was investigated. The results showed that titanium dioxide thin films produced with La3+ addition electrolyte exhibit higher photo-activity than pure electrolyte for the oxidation of rhodamine B. The removal of rhodamine B reaches 90% for 30 min when La3+ addition concentrate is 0.05 g/L. Experimental results of X-ray diffraction and atom force microscopy show that the increase in activity is related to change in the lattice parameters and cell volume.