Heat　transfer　deterioration　(HTD)　is　extremely　dangerous　for　the　supercritical　steam　generator　which　has　been　studied　for　many　years.　It　is　exceedingly　crucial　to　predict　the　onset　of　the　heat　transfer　deterioration　for　the　design　of　the　vaporizer.　In　this　study,　a　dimensionless　correlation　based　on　5662　data　from　15　independent　references　is　proposed　to　predict　the　onset　of　heat　transfer　deterioration　of　supercritical　fluids　in　vertical　circular　tubes.　Two　different　criteria　of　HTD　are　employed,　and　the　corresponding　dimensionless　correlations　have　mean　absolute　relative　deviations　of　12.75%　and　15.5%,　respectively.　The　new　dimensionless　correlations　not　only　improve　the　prediction　of　HTD　for　supercritical　water　compared　to　the　existing　correlations,　but　also　have　applicability　for　supercritical　CO2　in　a　proper　range.