The analysis of variations in water-sediment processes both in network-rivers and river-outlets at the Pearl River estuary, reveals that in recent three decades the water-sediment amount diverted towards southeast has get increased in network-rivers and hence, resulted in an increase of the flow distribution of the Lingding Bay, demonstrating the responses of human activities to the hydrodynamics of the estuary. Through the analysis of sediment transport, the tidal sediment-laden capacity is set up by taking account for the sediment flocculating settling. The preliminarily analysis of the estuary evolution indicates that the extensive human activities in recent three decades have changed the topographic and hydrodynamic features of the estuary, especially, the sediment mining from network rivers has caused a large amount of river-bed-sediment being excavated. The large-scale reclamation of beaches or shoals along coastal areas near the outlets has caused a significant influence on the evolution of the estuary.