Public participation in Environmental Impact Assessment (EIA) process has been implemented since the introduction of EIA project on August 1 1991, followed with Environmental Policy Act promulgation on August 1 1990. Though public participation has room for improvement. This study compared before and after the introduction of public participation on EIS preparation cost, project cost, EIS preparation term and project term through 293 EISs analysis. Also public opinions in EIS after introduction of public participation were analyzed. The results are expected to be contributed to the system improvement of public participation.