The nesting of the Fermi surface in a two-dimensional (2D) system is not perfect, which is distinctly different from one-dimensional system. The nesting deviation can heavily suppress the instability of 2D system. In this paper, the effect of the nesting deviation on the Peierls transition is quantitatively studied, and the limit for the nesting deviation, beyond which the Peierls transition is destroyed, is determined. Such a behavior is favorable to get the superconductivity.