Abstract: Focusing on the economic phenomena where perfect self-interest and/or perfect altruism may not lead to collective Pareto efficiency, this paper makes use of the GR game model and the GR equilibrium in Reference[1], builds a Cournot model based on the GR(golden rule) and explores the relationship between the collective Pareto efficiency of GR equilibriums and the weight systems(to characterize the degrew to which a firm take into account other firms).The results show that(1) in an N-firm Cournot mo del, the set of GR equilibriums is consistent with the set of strategy profiles with the collective Pareto efficiency if and only if all players attach the same weights to the profits of all players(including himself), and(2) in the two-firm context, a GR equilibrium has the collective Pareto efficiency if and only if there is(at least) one player who equally treats his own and his opponent's profts.These results enforce those in Reference[1] under Cournot competition, on the other hand, they imply that Cournot competition where each firm equally treats its own and his opponent' s profits will results in an equilibrium with collective efficiency.

Key words: GR game, GR equilibrium, collective Pareto efficiency, cournot model