中文摘要：

如何判定寡头三级价格歧视的福利效应是反垄断理论与政策的难点问题。采用差别产品寡头三级价格歧视模型分析发现，三级价格歧视的福利效应取决于产品差别化“竞争弱化效应”和价格歧视“竞争促进效应”的共同作用，寡头三级价格歧视并不注定所有消费者支付低价格和企业利润下降。寡头三级价格歧视的福利效应很大程度上受到消费者选择偏好的影响，并且消费者福利与社会总福利往往呈现出非同步变化的特点，带来更复杂的福利权衡。反垄断法应科学界定价格歧视，执法应采用“形式审查”与“效应审查”相结合的复合审查机制，并优先保护消费者利益。

英文摘要：

The welfare effect of oligopoly third - degree price discrimination is a difficult issue in eco- nomics theory and anti - monopoly law. This paper analyzes the competition effects of third - degree price dis- crimination in differentiated products oligopoly. The welfare effect of third - degree price discrimination de- pends on the combination of ＂competition weakening effect＂ of product differentiation and ＂competition promo- tion effect＂ of price discrimination. The consumer preference has important influence on equilibrium and wel- fare. Third -degree price discrimination will not lead to lower price for all consumers and lower profits for all firms. Third - degree price discrimination of differentiated products will promote the synchronous improvement of consumer welfare and total social welfare, and welfare trade - off will become more complicated. It should be defined correctly and form -effects test should be taken to protect consumers＇ welfare.