Abstract: The contact charge transfer (CCT) complex can be formed in the ground state between the α-pinene and oxygen. Under the irradiation of light with suitable wavelength which response to the absorption of CCT complex, it will be advantageous for the photooxidation of α-pinene. The effect of solvent polarity is presented evidently in the oxidation. The larger the polarity is, the faster rate of photooxidation the α-pinene has. All of these shows that charge transfer plays an important role in the reaction. In addition, the oxidation of α-pinene can also take place in complete dark conditions as a result of the CCT complex formation of α-pinene and oxygen. According to the analysis of products in photooxidation and dark oxidation, it is certain that the oxidation in our condition proceeds through a free radical mechanism.