To explore the occurrence characteristics and potential ecological risks of microplastics in the surface water of Tianjin, 6 typical rivers and reservoirs were selected as the research objects. This paper investigated and analyzed the occurrence characteristics of microplastics in surface water in October 2023, and used the Pollution Load Index(PLI) method, Polymer Hazard Index(PHI) method, Potential Ecological Risk Index(PERI) method, and Risk Quotient(RQ) method respectively to assess the ecological risks of microplastic pollution in the river basin area. The results indicated that microplastics were detected in all sampling sites, with the abundance ranging from 0.39 n/L to 8.18 n/L and an average abundance of 2.77 n/L. The dominant polymer types of microplastics were polyethylene terephthalate(PET), polypropylene(PP), and polyethylene(PE), accounting for more than 90% in total. The main shapes of microplastics were fragments and fibers with a size of 0.1 to 0.5 mm. The distribution patterns were mainly influenced by human activities, such as tourism, fishery activities, and agricultural production activities. Compared with domestic and foreign studies, the pollution of microplastics in typical rivers and reservoirs in Tianjin is generally at a medium to low level, with low pollution load risk and low potential ecological risk, while the polymer risk is at a high to extremely high level, and the risk quotient is at a medium level. The predicted no-effect concentration(PNEC) of microplastics in the surface water of Tianjin was calculated to be 13.81 n/L using the species sensitivity distribution method, showing no direct effect on aquatic organisms. However, it should still be noted that the cumulative effect of high-risk polymers in the environment may lead to greater exposure and more ecological risks. The research results can provide data support for the management, control, and prevention of microplastic pollution in the surface water of Tianjin.