The influence of annealing temperature in argon on capacitance-voltage and conductance-voltage characteristics of metal-TiO2-n-Si structures was investigated. For the structures not exposed to annealing, found out influence of value and sign of potential of gate on C-U and G-U dependencies. The change of flat band voltage (UFB) is conditioned by a height or reduction of mobile charge in a dielectric. While covering the light with λ = 400 nm increase in capacity and conductivity of structures is observed only at depletion potentials at the gate. Height of capacity and conductivity at large negative potentials on a structure during action of light is explained by appearance superficial E.M.F. When enriching the potentials after turning off the light initially increase in the capacity and conductivity is observed and their subsequent slow return to the values before the light. Height of maximum conductivity after turn off light with a subsequent gradual decline it is possible to explain the slow recharge of the superficial states.