The water absorption and desorption process of ceramsites with different prewetting degree embedded in lightweight aggregate concrete were monitored by a U tube micro pressure measurement device. The interfacial structure between ceramsites and hardened cement paste in lightweight aggregate concrete was scanned by SEM. By a new ring restrained shrinkage equipment, the tensile creep characteristics of lightweight aggregate concrete was also investigated. The study reveals that with the increase of ceramsite prewetting degree the ability of water absorption declines and the ability of water desorption increases for ceramsites embedded in lightweight aggregate concrete; the interfacial transition zone(ITZ) between ceramsites and hardened cement paste becomes denser, and the tensile creep of lightweight aggregate concrete declines.