Proper selection of dither amplitude and frequency of RLG influences the effect of dither bias directly. In order to reduce lock-in of RLG effectively, the width of dynamic lock-in is obtained by deducing the basic input-output equation of RLG in the article. Corresponding optimization model is based on the purpose of reducing the influence of dynamic lock in. The result of the optimization shows that it is necessary to enlarge dither depth to reduce the nonlinear influence. When dither depth is large enough, there is no evident effect on the reduction of dynamic lock-in by enlarging it further. However, dynamic lock-in may be reduced to zero by modulating dither depth locally with very small value according to the result of optimization. Some constructive conclusions are obtained in the end of the article.