In this study, PtCl_x, PtO_x and Pt^0 modified titanium dioxide nanotubes (TNTs) materials were prepared by impregnation, precipitation-calcination and photodeposition methods, and were applied to the photocatalytic degradation of methylamine. The results showed that the 0.5% PtCl_x/TNTs catalysts exhibited the best performance in the photocatalytic degradation of methylamine, with a photocatalytic efficiency of up to 95%, which remained over 92% after 6 h continuous operation. The effects of different chemical states of Pt on the performance of TNTs in the photocatalytic degradation of methylamine were investigated using XRD, TEM, BET, XPS, UV-Vis DRS, PL and ESR tests. When the Pt elements were loaded in the form of PtO_x and Pt^0, the adsorption process of methylamine on the surface of the catalysts was affected, although the light absorption and carrier separation properties of the samples were enhanced. This scenario was unfavorable for the photocatalytic oxidation process of methylamine. Only when the platinum element was loaded on the TNTs in the form of PtCl_x to construct anew Pt(III)-Pt(IV) electron transfer channel, the photocatalytic degradation performance of methylamine was significantly promoted.