Abstract: Cement-sheath shrinkage after the injection of cement slurry in an annulus has a detrimental effect on cement-casing interface. A lattice expansive agent can make up for the cement-sheath shrinkage, further studies, however, are needed on whether or not the lattice expansive agent can improve the consolidation strength of cement-casing interface. In this paper, we used a self-designed testing device to qualitatively measure the shear-cementing strength between expansive cement and casing, studied consolidation properties with variations in temperature and pressure, and compared the expansive cement with conventional one. In addition, a relationship between microstructures of cement-casing interface and macroscopic mechanical behaviors of interface consolidation was investigated. The results showed that the addition of lattice expansive agent could significantly reduce the consolidation strength of cement-casing interface and increased the elastic modulus of cement sheath, which could weaken the resistance of the cement-casing interface consolidation strength to variations in temperature and pressure. In order to meet the requirement of temperature and pressure conditions encountered in exploitation, it is significant to develop a new expansive agent that can be expansible and of help to improving the interfacial consolidation strength and mechanical properties of cement sheath.