A network stream capture tool has been developed to monitor and capture control data and information encapsulated in network stream for distributed control systems for high energy accelerator control systems. The tool allows capturing data streams between specific computers, and dumping the stream data into a file. The data can be browsed using graphic user interface (GUI), either binary, ASCII, UTF-8, and hexadecimal formats to analyze and debug communication protocol employed among computers for the control systems. The tool has been implemented using Java, and thus ported to various platforms, including Linux, Solaris and Windows, providing versatile functionality necessary for multi-computer control systems. This paper describes design and implementation of the network stream capture tool in detail.