中文摘要：

从构建市场结构、能力与产品线水平延伸关系的理论假设出发，运用泊松计数模型对180个混同样本数据进行了验证，主要结论包括：①市场集中度与企业产品线的水平长度显著负相关;竞争性品种的增加会导致容量有限市场中延伸激励的下降，而在高成长市场中则会引发跟随效应。②市场占有率越高，企业越有能力进入高端市场。③本土企业与合资企业的细分市场偏好存在显著的差异．产业内生命周期的延伸会影响延伸行为的变化。这些发现对本土企业优化产品线策略有参考价值．

英文摘要：

Starting from the theoretical hypotheses of the relationship between market structure, capacity and product line horizontal extension, the paper empirically tests 180 pooling data with Poisson model. Our main conclusions are as follows：（1） there is a significant negative correlation between the ratio of market concentration and the length of product line. The increase of competitive varieties will lead to the decline of extension incentives in the markets with limited capacity, which will further extend to the high-growth markets.（2） The higher market share a company owns, the better access it will have to high-end markets.（3） There are significant differences with preferences far segments between local companies and joint ventures. The life cycle of industry will affect the changes of extension behaviors. These findings will be helpful for local companies to improve their product line strategies.