This study investigated the effect of Pt added to V-TiO2 for high concentrated ammonia photodecomposition. Pt components were introduced to the V-TiO2 photoctalysts using two type's methods, a commonly sol-gel (Pt-V-TiO2) and impregnation (Pt-V-TiO2) methods. The X-ray diffracton (XRD) peaks which assigned to V2O5 at 19.5, 27.5 and 30.20° in V-TiO2, and Pt metals at 39.80° (111) in the Pt/V-TiO2 wrer seen. However, these peaks were not seen in Pt-V-TiO2, and Pt/V-TiO2=V-TiO2 after thermal treatment at 500°C. The NH3 decomposition slightly increased with vanadium addition compared to pure TiO2, and the Decomposition was more enhanced with Pt addition. Particularly, the NH3 decomposition reached 100% over Pt/V-TiO2 after 120 min, although about 10-30% of the ammonia was converted into undesirable NO2 and NO. We found that the partially oxidized NO and NO2 dominated over V-TiO2 and pure TiO2, respectively, while both molecules were reduced by Pt addition, in particular, they was more reduced in Pt-V-TiO2.