The microstructure and characteristic of fracture between TC4 titanium alloy and 1Cr18Ni9Ti stainless steel bonding joints were analyzed concretely in this paper. For direct SP/DB of TC4/1Cr18Ni9Ti, the diffusion layer joint was composed of some new phases such as β-Ti, TiFe2, TiFe, σ-FeCr and α-Fe, and the shear strength could be ensured when the thickness of TiFe/TiFe2 brittle phases was controlled within 3~5μm. In SP/DB of TC4/1Cr18Ni9Ti, the joint status of microzone in interface was asymmetric and exhibited different fractograph. The bonding area of fracture could be divided into three zones: similar original interface zone, metallurgical bonding zone and quasi-metallurgical bonding zone. The interface deficiencies were constitutive of mechanical bonding area, cavity and impurity.