1. A motion estimation method for a motion picture compression coding in a MPEG4-based motion estimation method, comprising the steps of: a) estimating an initial motion point; b) performing a Newton-Raphson operation using a MAD (Mean Absolute Difference) of the estimated motion point of step (a) as an objective function, and finding a new motion point; c) determining whether a difference between the new motion point of step (b) and the estimated motion point is less than a minimum error range, and using the new motion point as the estimated initial motion point when the difference is more than the minimum error range, and re-performing step (b); and d) determining whether a difference between the new motion point of step (b) and the estimated motion point is less than a minimum error range, estimating the new motion point as a final motion point when the difference is less than the minimum error range, and determining a motion vector using the final motion point.