The electrooxidation behavior of HCHO on a roughened platinum electrode was studied by cyclic voltammetry. Two factors that influence the electrooxidation behavior of HCHO, i.e. the concentration of the supporting electrolyte and the structure of the electrode surface were taken into account. The dissociative adsorption behavior of HCHO on a roughened platinum electrode was investigated by confocal microprobe Raman spectroscopy in-situ, and the spontaneous dissociative adsorption behavior of HCHO on a roughened platinum electrode was found by CV and was confirmed at the molecule level by in-situ Raman spectra.