Abstract: In order to logically and consistently understand how the factors,which have effects on the willingness to supply and the willingness to demand for farmlands,and market power make influence on the equilibrium quantities,prices and economic efficiency in the market for the circulation of farmlands,this paper builds up a supply-demand model based on farmers'and firms'optimal decision-making,solves the model and analyzes the equilibrium. The results show that(1)compared to the context of competitive market for the circulation of farmlands,monopoly leads to lower equilibrium quantities,prices and efficiency for given factors influencing the willingness to supply and demand;(2) given other factors,the influencing directions of one factor (influencing either the willingness to supply or the willingness to demand) on equilibrium quantities and prices are consistent in both competitive market and monopoly for the circulation of farmlands.

Key words: circulation of farmlands, willingness to supply, willingness to demand, equilibrium