We theoretically report a new method to achieve variable-in, variable-out wavelength conversion in LiNbO<sub>3</sub> with aperiodic optical superlattices (AOS) structure. The optimal structure of the LiNbO<sub>3</sub> sample was obtained through simulated annealing (SA) method. About 3.4nm prescribe pump bandwidth at 1559nm is achieved to fulfill variable wavelength conversion among four selected ITU signal channels (C23-C20). As the result of large pump bandwidth, the reduced effective nonlinear coefficient of the AOS sample decreases to 0.21. Fluctuation of the operation temperature, variation of the incident angle and the errors in poling process show little influence on the performance of the device.