The electric-field-induced strain in Rh-doped BaTiO3 single crystals increases with increasing ageing time at 80℃. After 27 days' ageing, the strain can reach 1.11% under bipolar field cycling conditions. However, the strain under mo nopolar field cycles is strongly dependent on the drive frequency and reaches as high as 0.95% at frequency of 0.01Hz. The hysteresis loop (P-E curve) of the aged sample is similar to a wasp-waisted hysteresis loop. Ageing can significant ly improve the electro-strain effect in the Rh-doped BaTiO3 crystal a nd make t he BaTiO3 crystal a promising and lead-free material for novel applic ations in ultra-large strain and nonlinear actuators.