中文摘要：

本文基于细分市场的产品定位和定价理论，利用中国轿车制造企业2000-2007年的微观数据，考察产品线竞争的多重效应，以发现不同细分市场之间产品线竞争的绩效差异。固定效应和结构方程模型的计量检验表明：（1）产品线长度的增加会显著地提高企业细分市场的占有率；（2）较长的产品线是实现“价格升水”或实施价格歧视的工具；（3）应对竞争者的延伸行为时，企业会选择“跟进”策略；（4）这三种效应在不同的细分市场间存在一定的差异。同时，市场规模变化、市场结构、竞争者反应等因素在不同程度上也影响着产品线竞争的实际效果。结合联立方程的初步估算，给出了研究的策略含义。

英文摘要：

Based on the segment market positing and pricing theory, the paper studies the multiple effects of the product line competition using the firm level data of the Chinese automobile manufacture from 200-2007.fixed effect and simultaneous equations tools are apply to test hypothesis and identify the performance differentiation between the segment markets. The results show that： （1）product line extend can increase the firm＇s segment market share; （2） a broad product line is a tool to raise price premium or discrimination; （3）the best reaction to product line competition was choice follow; （4） those effect was difference among the segment market, however the market growth, structure and rival behavior also play an role in the competition outcomes. Connect with the robust test with the simultaneous equations model, the paper also give some strategy suggestions for native firm＇s product line development.