In order to solve the problem that the traditional methods for assessing micro plastic pollution are not accurate, the research on toxic effects of micro plastic pollution on aquatic organisms and dynamic assessment methods has been proposed. In this paper, stereomicroscope and Fourier transform infrared spectrometer were used to identify the apparent characteristics and polymer composition of microplastics, and pollution risk index, pollution load index and ecological risk index were used to assess the ecological risk of microplastics pollution in the study area. The experimental results showed that the detection rate of micro plastic pollution in surface water was 20%∼100%, the highest detection value was 420ng/L, and the predicted ineffective concentration (PNEC) derived from chronic toxicity data such as development, reproduction and behavior was 1.36 × 10^-6 mg/L; The risk quotient calculated based on chronic toxicity is 0.03-36.76.