The reduction behavior of alpha platinum oxides on PtOx/Ti (fabricated by thermal decomposition) and Pt/Ti (reduced from PtOx/Ti) was compared using linear sweep voltammetry. The peak potential of alpha oxide reduction was found to shift to a less positive value with decreasing its hydration degree, which depended upon the lower potential limits and cycle number of cyclic voltammetry. Factors effecting the stability of various platinum oxides, including alpha and beta types, were systematically discussed in this work.