Controllable frequency conversion devices, with the generation of multiple-wavelength, are designed. We analyze the variation of light intensity in nonlinear crystal with propagation distance. A method is proposed to design nonlinear structure based on the distribution of light intensity. MATLAB software is used to simulate sum frequency generation. An aperiodic structure is obtained to achieve simultaneous six sum-frequency-generations. The weighting coefficient is introduced to flexibly modify output intensity and obtain objective spectrum with arbitrary shape. By analyzing sum-frequency-generation and second-harmonic-generation, the obtained structure can not only generate multiple-wavelength, but also arbitrarily adjust the optical power of output wavelength. Our proposed method has advantages of fast speed and high efficiency. It can provide a good guidance for the fabrication of nonlinear optical devices.