The effects of different types of microplastics (MPs) on the wastewater treatment efficiency of an adsorption-biological coupling system were investigated. The distribution of the microbial community and metabolic pathways in the coupled system were also analyzed. Biodegradable polybutylene succinate microplastics (PBS MPs) were added to reactor A, while non-biodegradable polystyrene microplastics (PS MPs) was added to reactor B. The average chemical oxygen demand (COD) removal rates in reactor A with 0, 50, and 100 mg/L of MPs were 95.34 %, 89.13 %, and 86.08 %, respectively; the average COD removal rates in reactor B were 96.84 %, 88.43 %, and 87.02 %, respectively. The average total phosphorus (TP) removal rates in reactor A were 74.14 %, 38.94 %, and 36.45 %, respectively, while those in reactor B were 71.73 %, 39.50 %, and 33.09 %, respectively. In the two reactors, Proteobacteria had the highest relative abundance (53 %–62 %), followed by Actinobacteria. PS MPs inhibited the expression of quorum sensing genes by influencing SecA and SecY. Horizontal transfer genes illustrated that both MPs led to up-regulation of reactive oxygen species (ROS)-related functional genes. During glycolysis, the abundances of glucokinase (GLK), pyruvate kinase (PK), and phosphofructokinase (PFK) in reactor A were 0.0179 %, 0.0133 %, and 0.0387 % higher than that in reactor B, respectively. Meanwhile, in nitrogen metabolism, the abundance of key genes such as nasA (A: 40.8 % B: 37.9 %) was greater in reactor A than in reactor B.