We propose a content-based parallel image retrieval system to achieve high responding ability.Our system is developed on cluster architectures.It has several retrieval servers to supply the service of content-based image retrieval.It adopts the Browser/Server (B/S) mode.The users could visit our system though web pages.It uses the symmetrical color-spatial features (SCSF) to represent the content of an image.The SCSF is effective and efficient for image matching because it is independent of image distortion such as rotation and flip as well as it increases the matching accuracy.The SCSF was organized by M-tree, which could speedup the searching procedure.Our experiments show that the image matching is quickly and efficiently with the use of SCSF.And with the support of several retrieval servers, the system could respond to many users at mean time.