1. A method for assessing data worth for analyzing yield rate, comprising the steps of: getting measured data with a plurality of data points, the plurality of data points corresponding to a plurality of control variables of semiconductor manufacturing; transforming the plurality of data points into a distance matrix with matrix distances, the matrix distances corresponding to differences of the plurality of data points under the plurality of control variables; expressing sample differences recorded in the distance matrix by two-dimension vectors and calculating similarity degrees of the two-dimension vectors and the distance matrix so as to take loss information as a conversion error value; calculating discriminant ability of the transformed two-dimension data and expressing the discriminant ability by an error rate of discriminant; and taking the conversion error value and the error rate of discriminant as penalty terms and calculating a quality score corresponding to the measured data.