Superplastic joining of 3mol% Yttria stabilized tetragonal zirconia polycrystal (3Y-TZP) is examined using 5wt%TiO2-doped 3Y-TZP as an insert material, in order to decrease the joining temperature and stress and to realize the local deformation near the joining surface. The joining tests are conducted by uniaxial compression in a temperature range of 1523 to 1723K. The joined specimen is characterized by a scanning electron microscopy (SEM), showing a clean interface with no cavitation. Four point bending tests are conducted to evaluate the joining strength, resulting an average flexural strength of 960MPa in the specimen joined at 1573K for sample compressed at 10MPa for 30 min, which is 80% of the strength of 3Y-TZP matrix. The temperature of 1573K is 100K lower than that obtained in sample without the insert material. Fracture occurs not at joining surface but at matrix in bending test. Residual stress is suggested to be introduced during joining process.