Abstract: Patent claim is the core of the patent, which determines the scope of legal protection of the invention. The number of patent claims may serve as an important characteristic of patent. However, few publications have been available for the relationship between the number of patent claims and the patent maintenance time. This paper explained the Logistic regression model in detail. It used the data of patent granted in 1994 from China, America, Germany, France, Japan and South Korea to analyze the effects of the number of patent claims on the patent maintenance time. The empirical results shows that the number of patent claims could affect the probability of the length of patent maintenance time. We also found that the circumstances are significantly different in Japan and South Korea. It also shows the limitation of research based on patent literature.