Abstract: An evolutionary game model of Cournot competition is studied.Two behavior rules can be selected by enterprise.One is"myopic"behavior rule,the other is Nash behavior rule.The probability of the enterprise choosing a certain behavioral rule is updated according to the replicator equation.Our results show that"myopic"behavior rule cannot be washed out by Nash behavior rule,and enterprise will select"myopic"behavior rule to make quantitative decision when it has certain rationality,and its rationality determines whether this game can reach equilibrium.

Key words: evolutionary game, behavior rule, Cournot competition