Abstract: Disclosed are a network traffic classification method and system based on an improved K-means algorithm. The method comprises: judging whether a total number NIC of network traffic data points in an initial clustering center set reaches an expected number k of network traffic clusters, if the k is not reached, calculating candidate metric values of network traffic data points in a high-density network traffic data point set, selecting a network traffic data point having the maximum candidate metric value, adding same into an initial clustering center set, removing the network traffic data point from the high-density network traffic data point set, then repeating the step until the total number NIC of network traffic data points in the initial clustering center set reaches the k, and ending the step. The method and system can ensure high network traffic classification accuracy.