Long time series of Antarctic sea ice extent(SIE) are important for climate research and model forecasting. A historic ice extent in the Ross Sea in early austral winter was rebuilt through sea salt ions in the DT401 ice core in interior East Antarctica. El Ni?o-Southern Oscillation(ENSO) had a significant influence on the sea salt deposition in DT401 through its influence on the Ross Sea SIE and the transport of sea salt inland. Spectral analysis also supported the influence of ENSO with a significant 2–6 a periodicity band. In addition, statistically significant decadal(10 a) and pentadecadal(50–70 a) periodicities suggested the existence of a teleconnection from the Pacific decadal oscillation(PDO), which originated from sea surface temperature anomalies in the tropical Pacific Ocean. The first eigenvector of the empirical orthogonal function analysis(EOF1) showed lower values during the Medieval Warm Period(MWP), while higher values were found in the Little Ice Age(LIA). A higher frequency of ENSO events were found in the cold climatic stage. The post 1800 AD period was occupied by significant fluctuations of the EOF1, and PDO may be one of the influencing factors. The EOF1 values showed moderate fluctuations from 680 BC to 1000 AD, showing that the climate was relatively stable in this period. Long time series of Antarctic sea ice extent (SIE) are important for climate research and model forecasting. A historic ice extent in the Ross Sea in early austral winter was rebuilt through sea salt ions in the DT401 ice core in interior East Antarctica. El Ni o-Southern Oscillation (ENSO) had a significant influence on the sea salt deposition in DT401 through its influence on the Ross Sea SIE and the transport of sea salt inland. Spectral analysis also supported the influence of ENSO with a significant 2-6 a periodicity suggests the existence of a teleconnection from the Pacific decadal oscillation (PDO), which originated from the sea surface temperature anomalies in the tropical Pacific Ocean. The first eigenvector of the empirical orthogonal function analysis (EOF1) showed lower values ​​during the Medieval Warm Period (MWP), while higher values ​​were found in the Little Ice Age (LIA). A high er frequency of ENSO events were found in the cold climatic stage. The post 1800 AD period was occupied by significant fluctuations of the EOF1, and PDO may one of the influencing factors. The EOF1 values ​​showed moderate fluctuations from 680 BC to 1000 AD, showing that the climate was relatively stable in this period.