Pre-deformation to various degrees was imposed to the U-Nb alloy; afterwards the strain-recovery behavior of the alloy was investigated by the self-made strain-measuring equipment. The deformation mechanism and shape memory effect (SME) of the U-Nb alloy were investigated by TEM and XRD. The results show that growth, swallow and preferred orientation of high density twins is the primary deformation mechanism for U-Nb alloy at the initial stage of deformation, and it is considered that U-Nb alloy possesses excellent shape memory effect. The maximum reversible strain reaches to 3.2% during heating; reorientation and splitting through phase reversion of enlarged twins during reheating is the main reason for the shape memory effect of U-Nb alloy