The effects of recycled aggregates on the properties of capillary negative pressure and interfacial transition zone （ITZ） of concrete were studied， and the effects of different recycled aggregates on the early cracking risk and interfacial micro-morphology of concrete were analyzed. The results show that the capillary negative pressure curves of natural stone concrete （NSC） and recycled mortar aggregate concrete （RMC） are similar， and the aggregates have no obvious water absorption and release in the process of cement hydration. Compared with dry recycled brick aggregate concrete （D-RBC）， the capillary negative pressure of water saturated recycled brick aggregate concrete （S-RBC） increases. The change of capillary negative pressure of S-RBC is gentle， the cement hydration is sufficient， and the cracking time is delayed. The ITZ hardness and elastic modulus of D-RBC are slightly lower than that of S-RBC. In the actual preparation of recycled brick aggregate concrete， the bricks can be saturated with water， the risk of early cracking is the lowest， and the reduction of mechanical properties is not obvious.