This paper mainly introduces the designing procedure and realization of the network tool software based on Jpcap. The software is developed using JAVA language under the Windows system. Using this software, we can get the information of network card, capture and send packets. The Graphical User Interface (GUI) of the software is friendly. The information of the network card that we choose can be seen. The UDP packets that we defined can be sent. Moreover, the network connectivity can be tested through the method of PING.