The article reported the reduction of methylene blue (abbreviated as MB) by ascorbic acid (abbreviated as AA) in aqueous solution. The kinetics study revealed that the reduction proceeds of MB by AA was the pseudo first order reaction. In addition, the electrochemical property of reductant AA was investigated by cyclic voltammetry (CV). The CV result indicated that the electrochemical oxide of AA was diffusion controlling at glass carbon electrode (GCE).