1. A method of using MPEG-7 in the object segmentation, comprising the steps of: extracting the feature of an existing video object Plane (VOP) by the MPEG-7 technique, storing it in an MPEG-7 database and presetting a value; segmenting an input video image into a plurality of regions by color transformation and the Watershed process; setting the merge adjustment condition using a merge means and a threshold value to minimize the number of regions segmented; finding all possible region combinations using a region selector; finding the highest similarity region combination using a comparator to compare the VOP features stored in the MPEG-7 database to all possible region combinations found by the region selector and outputting the highest similarity region combination as a target VOP, wherein, the threshold value is reduced to increase the number of regions segmented if the target VOP is greater than the preset value and the threshold value is increased to reduce the number of regions segmented if the target VOP is smaller than the preset value, so that the highest similarity region combination output is more similar to the VOP in the input video image; repeating the acquisition of highest similarity region combination step until the adjusted threshold value meets any of the preset values and the value zero; and outputting the highest similarity region combination, after the threshold value adjustment is completed, as the final target VOP.