The invention discloses a taxpayer group association method for digging up a taxable amount jump reason. The taxpayer group association method includes 1, according to current and historical tax payment information of a taxpayer, granting weight to a taxpayer node in a taxpayer benefit association network; 2, by the aid of a dense subgraph mining algorithm, finding a taxpayer group with taxable amount jump and close association from the taxpayer benefit association network. In this way, the taxable amount jump is might excited by abnormal commercial activities. The taxpayer group association method integrates the taxpayer benefit association network to serve as the reference for the monitoring of the tax payment activities and the relative commercial activities.