The influences of semi-conductive TiO2 with different crystal structures on the initial corrosion behavior of copper in dark conditions were investigated. Results showed that anatase TiO2 showed "corrosion-promotion activity" to copper, while rutile TiO2 did not. It is revealed that the "corrosion-promotion activity" is associated with TiO2 crystal structure and mainly dominated by the work function of TiO2. When the work function of n-type TiO2 is higher than that of copper, electrons are inclined to transfer from copper to TiO2. In addition, higher electrical conductivity and oxygen reduction reaction activity of TiO2 facilitate the electron consumption at the TiO2/electrolyte interface.