Abstract: A method and an apparatus are for classifying data. In an embodiment, the method includes: classifying at least two pieces of data, to obtain at least two data clusters; determining a bias degree of classification; re-classifying the at least two pieces of data by merging any several of the at least two data clusters; determining a bias degree of re-classification; and determining, by comparing the bias degree of first classification and the bias degree of re-classification, which classification is more accurate. By way of the method and apparatus, a related data cluster can be found from multiple data clusters for better data analysis.