1. A method for detecting touch-point coordinates, comprising: (a) scanning a plurality of signal points in sequence to generate a plurality of original data including a plurality of original touch point data, wherein each of the plurality of signal points corresponding to an original touch point datum is defined as a touch signal point; (b) enduing each of the touch signal points with an identification code and grouping the touch signal points into a plurality of group sets according to the identification codes; and (c) calculating a barycentric coordinate of each of the group sets and outputting the barycentric coordinate as a touch-point coordinate of each of the group sets; wherein step (b) comprises: judging whether a current touch signal point neighbors one or more previously scanned touch signal points; when the current touch signal point neighbors a single previously scanned touch signal point, enduing the current touch signal point with a same identification code as that of the previously scanned touch signal point; and when the current touch signal point does not neighbor any previously scanned touch signal point, enduing the current touch signal point with a new identification code; detecting an amount of the neighboring touch signal points of the current touch signal point; changing at least one of the identification codes of the neighboring touch signal points to make the identification codes of the neighboring touch signal points be identical when the amount of the neighboring touch signal points is more than one and the identification codes of the neighboring touch signal points are different; and grouping the touch signal points with the same identification code into a same group set.