To explore the effect of subcritical water on citrus pectin， rheological properties and molecular weight of pectin treated by subcritical water under different temperature were studied in this paper. It was found that with the increase of subcritical water temperature and treatment time， pectin solution changed from pseudoplastic fluid to dilatant fluid， and the apparent viscosity decreased gradually. The molecular weight of citrus pectin decreased gradually， with the minimum molecular weight of 23.7 ku for number-average and 44.5 ku for weight-average， and the degradation degree of pectin was up to 80.5% and 71.7%， respectively. The content of reducing sugar in pectin solution increased gradually， and the hydrolysis degree of total sugar reached 75.1%. In addition， the degradation rate of pectin macromolecules did not change with time at a specific temperature. It is indicated that the subcritical water produced by high temperature and high pressure sterilization used in food processing has a great influence on the macromolecular structure of citrus pectin， which is worthy of further study.