This research indicates that the gradient of internal relative humidity (IRH) decreases rapidly within 7-day curing age in HPC.The amount of water imported by pre-wetted light-weight aggregate can regulate IRH of concrete.By importing a proper amount of water, the process of the decline of IRH can be delayed and the antogenous shrinkage can be reduced.The relationship among the amount of water imported by pre- wetted lightweight aggregate, IRH and AS was established.The result provides a new method of reducing early AS and enhancing early cracking resistance of HPC.