The invention discloses a port water area ship traffic risk early warning method. The method comprises the following steps: S1, starting a system, and detecting a working state of port water area shiptraffic risk early warning in real time; S2, judging a port water area ship traffic risk early warning working state; S3, carrying out risk cause analysis information and risk early warning mechanisminformation; S4, performing information fusion processing on the acquired risk cause analysis information and risk early warning mechanism information; S5, according to a ship collision risk measurement model, combining the risk cause analysis information and the risk early warning mechanism information; S6, constructing an early warning index system; S7, generating a rough set reduction index according to different risk values; S8, constructing an SVM training model by using a modeling software SVM algorithm; S9, carrying out precision inspection; and S10, giving an early warning result.