The primary goal of evaluation system of post-legislation is to test legislative text quality and implementation effect through data acquisition and analysis, so as to find out the problems and improve the legislation. The scientificity of evaluation system of post-legislation is based on realistic foundation, technical foundation, and philosophical foundation, which is not infinite; there are limitations in the cultural background, the scope of evaluation, and evaluation results. Legal Performance Evaluation Report on Idle Land Disposal Methods is a representative sample for analyzing the limitations, which can provide beneficial enlightenments for the practice of evaluation system of post-legislation.