An optimal correlation matching method for determining track behavior, which applies a video stream having a first image and a second image for locating a motion vector associated with a block of the first image in the second image, wherein each image has a plurality of blocks in rows and columns and each block has a plurality of pixels in rows and columns. The method divides a search window into a plurality of search subdivisions, selects one from the subdivisions as an operating search window, locates a center of a block respectively at all positions of the operating search window such that upon each position of the center located, pixels of the block of the first image in accordance with the operating search window are applied to corresponding pixels of the second image for performing match operation, thereby reducing required number for match operation.