The photoelectrochemical behaviours of dye-sensitized nanoporous TiO2 solar cells are studied under influences of light intensity, redox couple concentration, temperature, different cations and water in the nonaqueous solution. The value of the ideality factor of dyed nanoporous TiO2 film is determined to be 1.08. The diode behaviour of the dyed nanoporous TiO2 film approaches an ideal rectification characteristic. The rate of the reaction of I-3(-) with the electron at the surface of the dyed TiO2 electrode is of first order, like the reduction of I-3(-) at the Pt electrode. By analysis of the relationship of the photovoltage with temperature, the activation energies of the back-reaction for dyed nanoporous TiO2 electrodes in different solutions are obtained. Cations of different kinds and water are found to modify the interfacial properties of the dyed TiO2 electrode. Finally, a quantitative relationship between the short-circuit photocurrent and the light intensity, the I-3(-) concentration is obtained and used to explain the diffusion-controlled photocurrent. The corrected diffusion coefficient of I-3(-) is 5.4-6.2 x 10(-6) cm(2)/s in a CH3OCH2CN solution.