Given a query vertex in a graph, the task of community search is to find all meaningful communities containing the query vertex in an online manner. In this demonstration, we propose a novel query processing system for searching and visualizing communities in graphs, called VizCS. It exhibits three key innovative features. First, VizCS adopts several community models and supports community search on dynamic graphs where nodes/edges undergo frequently insertions/deletions. Second, VizCS offers a user-friendly visual interface to formulate queries and a real-time response query processing engine. Last but not least, VizCS generates a community exploration wall by offering interactive community visualization, which facilitates users to in-depth understanding of the data. Furthermore, VizCS becomes a community search platform that can visualize and compare different community results by various state-of-the-art algorithms and user-uploaded approaches.