The Ross Sea is a deep bay of the Southern Ocean in Antarctica, which lies to north the of the Earth’s largest ice shelf, the Ross Ice Shelf (RIS). Warm Circumpolar Deep Water (CDW) intrude onto the shelf can reach the RIS on the Eastern Ross Sea Shelf (ERSS), which may be a potential threat to the basal melting in the background of climate change in the future. A Southern Ocean State Estimate (SOSE) is used to calculate the heat budget over the year 2005–2010 on the ERSS. The results indicate that in the sub-surface layer, the tendency of the heat budget dominated by horizontal advection, and has a decline trend in 2006 and raised in 2007. Interannual variations of the heat budget in the ERSS are dominated by CDW intrusion from the North Boundary (NB, open sea) and HSSW movement from the West Boundary (WB, Western Ross Sea). The local wind stress curl over the main entrances of CDW intrusion is the forcing mechanism of the heat advection from the NB. The variations of HSSW volume dominated the heat advection from the WB, and is the main forcing mechanism for the sharp drop of the heat budget in the 2006.