Subcooled boiling model suitable for high pressure and high subcooling condition was established based on two-fluid model.The influence of liquid subcooling and wall heat flux on heat characteristics was investigated.The results show that distribution of gas phase throughout the cross section is nonuniform，and bubbles are intensive near the wall.The volume fraction increases with decreasing entrance subcooling which prompts the boiling heat transfer.With increasing heat flux，the surface heat transfer coefficient generally increases along the axial direction，however，decreasing tendency can be observed in local area，which becomes unclear with decreasing entrance subcooling.