Solid state diffusion bonding (SSDB) was employed to join high Cr ODS ferritic steel (Fe-15Cr-2W-0.2Ti-0.35Y2O3) blocks under uni-axial hydrostatic pressure using a high vacuum hot press, and the microstructure and mechanical properties of the joints were investigated. High Cr ODS ferritic steels were successfully bonded with free of precipitates and micro-voids at bonding interface by SSDB. The joint had nearly same tensile properties at room temperature with the similar anisotropic behavior to base material. Tensile strength of joint region at elevated temperatures is almost same with the base material, while the total elongation was decreased at 700°C. Although a small DBTT shift was observed in the joints, the upper shelf energy was increased significantly in a case of joints with L-R orientation.