Though load distribution and anchoring mechanism of prestressed cable have been studied by lots of tests and theoretical analysis，the load distribution variation over time of inneranchor segment and its relationship with anchor effective prestress are seldom studied. Based on in-site test of prestressed cable in a hydraulic power station, the authors analyzes the displacement of inner-anchor head and the nonlinear load transfer of inner-anchor segment during anchor pulling, and the variation of load distribution over time in inner-anchor segment. The relationship between load distribution variation and anchor effective prestress variation after anchor locked is studied also. Through the research, it is found that the stress of inner-anchor segment of tension-concentrated anchor cable is seriously concentrated, and the loads are transferred and adjusted from the initial point of inner-anchor segment to the end at the early stage of cable lock. But with continuous decreasing and stabilizing of cable effective prestress, the load transfer of inneranchor segment stops；and subsequently the loads of the whole inneranchor segment are reduced to a steady state. At last, the variation laws of interior bond section and cable effective prestress become similar.