中文摘要：

近年来，软件产业一直深受盗版的危害，软件企业需要制定相应的知识产权保护策略。考虑在纵向差异的软件市场，即消费者对软件质量存在偏好，同时市场上存在盗版的软件，新技术软件企业进入市场后，原有垄断软件企业和新技术软件企业应分别采取怎样的保护策略，使得企业获得利益最大化；据此建立模型，并通过对模型的分析表明，新技术软件企业进入后，原有技术软件企业应采取不保护的措施；原有技术软件企业和新技术软件企业都应该采取一种简单和低成本的保护措施；新技术软件产品的质量越高，新技术软件企业越倾向于采取不保护的措施。

英文摘要：

In recent years, piracy has a deleterious impact on the software industry, therefore the software companies need to develop appropriate intellectual property protection strategy. This paper considers a vertically differentiated market, which means that software products compete in quality, meanwhile there is pirated software in the market. When a new technology software company enters the market, the original monopoly software company and the new technology software company should take what kind of protection strategies, thus enabling companies to maximize benefit. Based on this, we establish a model and the model analysis suggests that when a new technology software company enters, the original software company should adopt a non-protection strategy. The original technology software and the new technology software companies should adopt a simple and low-cost protection measures. When the new technology company produces relatively high quality software, the new technology software companies tends to adopt a non-protection strategy.