In order to reveal the aggregation behavior of anionic-nonionic surfactant in oil-water interface，and provide theoretical guidance for the selection and application of surfactant in tertiary oil recovery， the interfacial properties of cardanol polyoxyethylene ether sulfonate（CPES）in decane-water system were studied by molecular dynamics simulation in terms of CPES concentration，temperature，salt concentration and types. The results showed that CPES had excellent interfacial activity. The interfacial tension was 1.83 mN/m when CPES was in saturated solution. The sulfonic group was main hydrophilic group of CPES. CPES had excellent temperature resistance. When the temperature ranged from 298 K to 373 K，the maximum interfacial tension was 16.74 mN/m. CPES had fine salt tolerance. When the concentration of Ca²⁺ increased from 0.10 to 0.35 mol/L，the number of hydrogen bonds between CPES and H2O was almost the same，and the range of interfacial tension was 12.605±1.745 mN/m. Three cations were arranged according to their influence on interfacial property of CPES in following order：Na⁺ ＞Ca²⁺＞ Mg²⁺. CPES had excellent interfacial activity and strong temperature resistance and salt tolerance，which was a good alternative surfactant used in oilfield exploitation.