The hydrological aberrance point occurred when the system changed from one state to another state. Based on the runoff time series of phase space reconstruction

the relative correlation distance entropy (H-d) was presented for identifying hydrological system status. H-d reflects the distribution and shape of the attractor in reconstructed phase space. It can represent some of intrinsic properties of the system .By analyzing the variation of H-d，the hydrological aberrance point can be recognized. The data on Monthly runoff of 50 years at Boluo Hydrologic Station were applied for a case study.The results showed that the method given in this paper is feasible for identifying the hydrological aberrance point

especially for the time series with numerous common aberrance points. The aberrance point at Buluo station occurred in 1972. The runoff is mainly affected by rainfall and also affected by hydraulic engineering activities.