In order to improve the coordinate accuracy of thermometer hole of tire for the manipulator based on stereovision and meet the requirement that manipulator gets the temperature of tire in real time, an available algorithm is using region matching based on epipolar line restriction to determine two matching points, but the algorithm requiring to calculate region grayscale for all points on the epipolar line will lead to huge calculation and low matching accuracy. Based on the principle of the corresponding points possessing similar grayscale value, an improved algorithm comparing the target pixel point with each pixel point on the epipolar line in the aspect of grayscale firstly and then calculating region grayscale for the points possessing similar grayscale value to target point was proposed. The algorithm excludes some non matching points on the epipolar line, which can reduce the amount of computation and drop the false match rate.