Distributed Smart Camera Network can be seen as a network with smart camera around every corner. Smart Camera is an embedded vision system which integrates Sensing Unit, Processing Unit and Communication Unit in one single box. The goal of smart camera is to observe what is happening in the surveillance scene, extract specific information and then transform it to the host or take appropriate action automatically. This paper aims to provide an introduction of smart camera first, including its architecture, platform, challenge etc. We then describe the difficulties when coming to the reality environment, including calibration to get camera topology, camera selection and hand-off for tracking, information fusion, distributed video coding, privacy and security etc. A summary of work on these topics is also given before the conclusion. This paper reviews some promising patents on distributed smart camera network.