In this paper, we present a novel region-based color image retrieval system using geometric properties. A region-growing technique is firstly employed to cluster the connected color pixels with the same color in an image to form color regions. Then, two most important descriptive geometry features are extracted. One is the spatial relational graph (SRG); another is the Fourier description coefficients (FDCs) of each color region. In the matching stage, the modified relational distance graph matching between two SRGs is performed firstly to find the best matches with the minimum relational distance. Then, the shape matching is applied to obtain the best vertex match with the minimum geometric distance. Experimental results reveal the feasibility of our proposed approach in solving color image retrieval problem.