Display omitted •Built a system of river ecological evaluation indexes and the evaluation model for plain river network area.•A case study of typical rivers’ ecological status in Jiangsu Province.•Rivers’ ecological status deteriorates as urbanization levels rise.•Correlation of river ecological status characterization factors, comprehensive index and ISC.•The reference value of the ISC red line of river ecological quality from good to medium. With the rapid economic development and continuous growth of urbanized area, the ecological status of rivers is undergoing profound changes, especially in the plain river network area, which will have a negative impact on the sustainable development. In order to systematically evaluate he ecological status of rivers, the river ecological status of rivers of 21 main streams and tributaries in Jiangsu Province was evaluated in the context of urbanization in this article. A system of river ecological evaluation indexes and the evaluation model for plain river network area were built, with 4 indexes of aquatic environment, natural ecological system, social service function and water management and protection, as well as 12 pieces of divided criteria. The ecological status of these rivers in Jiangsu Province was assessed as s a case study, and 71.4% were deemed to be in good condition. Simultaneously, we investigated the fluctuations in river ecological status under different levels of urbanization, as well as the relationship between river ecological status and ISC, to investigate the link between urbanization and river ecological status (impervious surface cover). The results showed that, rivers' ecological status deteriorates as urbanization levels rise, and there is a significant negative correlation between urbanization level and comprehensive index, water quality, riparian vegetation coverage, the embankment compliance rate, and the water quality compliance rate in water function areas. Furthermore, according to the linear fitting results, the reference value of the ISC red line of river ecological quality from good to medium, directing the ecological river building and urbanization planning, is at a rate of 28 %.