1. A method for motion estimation for use in video coding, when a first block in a current frame being coded, the method being used for searching for a second block in a previous frame matching the first block in the current frame, the second block being used for determining a motion vector, in a predetermined search region, for the first block, the predetermined search region having a plurality of rows, the plurality of rows including an (N−2)-th row, an (N−1)-th row, an N-th row, an (N&plus;1)-th row, and an (N&plus;2)-th row, each of the plurality of rows having a plurality of points, wherein a prediction point is on the N-th row, the method comprising the steps of: (a) choosing all points of the (N−2)-th row, the N-th row, and the (N&plus;2)th row as checking points; (b) calculating block match errors for the checking points and defining a checking point which corresponds to a minimum block match error as a candidate checking point; (c) determining whether the candidate checking point is on the N-th row; if the candidate checking point is on the N-th row, proceeding to step (g); otherwise, proceeding to step (d); (d) determining whether the candidate checking point is on the (N&plus;2)-th row; if the candidate checking point is on the (N&plus;2)-th row, proceeding to step (e); otherwise, proceeding to step (f); (e) incrementing N by two, choosing all points of the (N&plus;2)-th row as checking points, and repeating the step (b); (f) decrementing N by two, choosing all points of the (N−2)-th row as checking points, and repeating the step (b); and (g) choosing all points of the (N−1)-th and the (N&plus;1)-th rows as checking points, calculating block match errors for the checking points, and defining a checking point corresponding to the minimum block match error as the candidate checking point, wherein the candidate checking point corresponds to the second block and is used for determining the motion vector for the first block.