Faced with the problems that a good active distribution network cluster division method does not exist in the prior art and cluster division based on an active distribution network system is still in an exploratory stage at present, the invention provides an active distribution network cluster division method based on equivalent impedance. The method includes the steps of taking the equivalent impedance between nodes in an active distribution network system as a quantized parameter for representing an electrical distance between nodes; performing cluster division for the nodes in the active distribution network system according to the electrical distance between the nodes; and identifying, in all cluster division modes, a cluster division mode with the minimal electrical distance between the nodes in a cluster and the maximal electrical distance between the nodes between clusters, as an optimal cluster division mode. According to the invention, the equivalent impedance is used as the quantized parameter for calculating the electrical distance, then the cluster division is performed based on a K-means algorithm, finally, a multi-objective objective junction is established to determine the advantage and disadvantage of the cluster division, and a most effective cluster division result is given.