The hot cracking phenomena and phase behaviors during hot working process of Cu- Ni bearing hot rolled steels were investigated by a 90℃ bending test, BSE image analysis and EDS analysis. For a Ni-free 1.2%Cu bearing steel, the surface hot cracking occurred above 1100℃ due to a liquid state Cu-enriched phase formed continuously at the interface between oxide scale and matrix. The liquid Cu-enriched phase penetrated into austenite grain boundaries and caused surface cracking during the hot working. In case of O.6%Ni containing L2%Cu-Ni bearing steel, solid state Cu-Ni-riched phase existed at the scale/matrix interface as a discontinuous type. But the higher addition of 1.2% Ni, solid state Ni-Cu-riched phase was formed dominantly in the oxide scale. It was found that the addition of Ni suppressed the surface cracking of 1.2%Cu bearing steel by eliminating the liquid state Cu-enriched phase.