Abstract: As a new type of pollutant, microplastics (<5 mm in particle size) has attracted more and more attention in recent years. The abundance and distribution of microplastics in the sediments of six sampling sites along Beitang Drainage River, an important drainage river in northern Tianjin, were examined. The pollution status of microplastics was evaluated by constructing a fuzzy evaluation model of microplastics pollution based on triangular fuzzy numbers. The results showed that the abundance of the microplastics in the sediments of Beitang Drainage River ranged from (183.50±11.33) to (238.00±12.93) ind/kg (based on the dry weight of sediment). Three types of microplastics, namely fragment, fiber and film were mainly separated from the sediment. Fragment accounted for the largest proportion (44.92%-56.40%), fiber accounted for the second (35.35%-44.52%), and film accounted for the smallest. The studies of the particle size of microplastics also indicated that the microplastics with particle size less than 1 mm and 1-2 mm accounted for over 80% of the total microparticles in each sampling site, while the microplastics with particle size more than 2 mm accounted for a small proportion. The microplastics in the sediments of Beitang Drainage River was in moderate and severe pollution level. Compared with the results of the deterministic evaluation results, the fuzzy assessment result could give the possible value range of pollution index and the subordinate credibility level, which could effectively reduce the uncertainty caused by different spatial heterogeneity of sediment, analysis methods and analysts, and better characterize the pollution status and the spatial distribution differences of the microplastics in the sediment of the studied region, which was more objective and comprehensive.