Abstract: In order to study the coordination of ecological,economic and social benefits to achieve an optimal model of conversion of farmland to forests(CFF),we investigated Liangcheng County,Inner Mongolia Autonomous Region,which is a typical site of CFF.Based on system dynamics(SD),this investigation adopted five technical methods combining observations at field stations and extensive investigations. Over(10 000) original data were obtained in the investigation.The results show that the optimal model in Liangcheng County is a mixed stand of Prunus armeniaca + Hippophae rhamnoides + Medicago sativa.The model contains specific supporting technologies and operational mechanisms.