A new color feature obtained from the pruned octree color representation of an image for interactive image retrieval is proposed in this work. The pruned octree is constructed based on a natural color clustering of a given image rather than the fixed bucket color quantization of the entire database. In this new framework, we integrate commonly used features such as color width, color depth, average colore and multi-resolution colore distributions. As a result, it supports flexible filtering, in which the similarity matching procedure can be gradually refined. Examples are given to illustrate the query image analysis and sequential filtering strategy based on the octree color feature.