Based on periodically poled lithium niobate (PPLN) waveguides，an all-optical single-photon wavelength conversion scheme is proposed, in which a cascaded sum-frequency generation (SFG) and difference-frequency generation (DFG) are applied. In the Heisenberg picture, the annihilation operators of target photon are obtained by using the Hamiltonian of nonlinear conversion process. According to the efficiency of the single-photon wavelength converter, that is, the ratio of the value of photon number operator after conversion to the value before conversion, the relation of the efficiencies of the single-photon wavelength converters in the SFG and DFG process with the pump power are analyzed. The result that there exists an optimum pump power with which the quantum state can be transferred completely is demonstrated. Numerical analysis results show that the efficiency of single-photon wavelength conversion from 1 550 nm to 1 530 nm is about 61% when the pump power of up-converter is 65 mW and the pump power of the down-converter is 150 mW, respectively. In addition, an experimental setup is also proposed, which consists of PPLN waveguides, pump lasers, quasi-single photon source, optical components, e.g. filtering, single photon detector (SPD) and synchronization circuit.