A measurement study of a campus Wi-Fi network with mixed handheld and non-handheld traffic Handheld and non-handheld devices, which are simultaneously online, constitute the regular clients of the campus wireless local area networks (WLAN). It is necessary to understand the patterns of the user distribution and the user behavior, and adopt better strategies to optimize the service, as well as to understand the students’ daily life. This paper introduces a approach of understanding how campus WLAN performs and how the users behave. In the analysis, many interesting phenomenons and problems are discovered. We capture all of the packets in a campus free Wi-Fi during the experimental period. We articulate an approach to describe the user distribution from the view of the traffic variation tendency and the network performance. And the user behavior patterns are described from two aspects, the popular websites and the behavior of downloading files. Furthermore, after revealing the problems of the network, practical suggestions is proposed for improvements in different aspects.