1. An intention identification method for tracking and predicting an movement of a pattern of first object captured by a video camera and received by a computer in order to determine an intention of a user and thereby operate the computer, comprising the steps of: processing the pattern and converting the pattern into a plurality of pixels; analyzing a variation trend of the pixels, based on variation of the pixels in any direction relative to a preset geometric center of the pixels in order to obtain a quantity representative of a direction and moving amount of the pixels for comparison with a respective characteristic curve so that the intention of the object may be determined; and operating the computer according to results of the intention determination, wherein the characteristic curve is formed by a non-activate region set with respect to center point of the pixels, and an activate region set with respect to the center point of pixels and which is larger than that of the non-activate region, wherein during formation of the characteristic curve, a further quick action region is formed with respect to the center point of the pixels, which is larger than the activate region, and wherein the step of obtaining a quantity representative of a direction and moving amount of the pixels comprises the steps of: (a) capturing an image of a background object and transferring the captured background object image to the computer; (b) setting pixel data extracted from the background object image as reference data, constructing a reference coordinate system including X, Y, and Z coordinate axes with respect to said center of the pixels of the reference data, and analyzing said trend of said pixels in said reference coordinate system, said pixel data being selected based on lack of movement of said pixel data within a predetermined time period; (c) using an integral trend judging method to detect movement of the first object relative to said X and Y coordinate axes, using a variation ratio of movements relative to the respective X and Y coordinate axes to determine a movement trend for the first object; and (d) determining that the object has moved if the movement trend is some direction is over a threshold, and deriving said quantity representative of a direction and moving amount of the pixels.