Abstract: Some heavy metals and antibiotics are widely used as feed additives in livestock breeding in rural areas. However, the bioavailability of the additives is quite low, while 40%—80% are discharged in the forms of prototypes or metabolites in feces, which causes a series of environmental pollution problems. Constructed wetlands (CWs) are sewage treatment technology with advantages of low costs, high efficiency and easy maintenance. Earlier studies have been reported that CWs have efficient removal effect on conventional pollutants such as N, P and COD, but there are few studies on the simultaneous removal of heavy metals and antibiotics in the tail water of livestock and poultry breeding in CWs. The influence and mechanism of combined pollution on the treatment effect of CWs is not clear yet. In this study, based on comprehensively considering the additives in aquaculture feed and their toxic effects, copper (Cu) and sulfamethoxazole (SMZ) were chosen as target pollutants. A group of five small-scale vertical flow constructed wetlands (VFCWs) were constructed, while different concentrations of Cu and SMZ wastewater were prepared to simulate different combined pollution levels (A: blank, B: 2 mg/L Cu, C: 2 mg/L Cu and 5 mg/L SMZ, D: 20 mg/L Cu and 0.2 mg/L SMZ, E: 20 mg/L Cu and 5 mg/L SMZ). The effects of combined pollution Cu and SMZ on the purification capacity of wetland system were then explored. Results showed that VFCWs had high removal rate and relatively stable removal effect of total phosphorus (TP), chemical oxygen demands (COD) and nitrate nitrogen (\rmNO_3^-\text-N ) under different combined pollution levels, while the average removal rate was higher than 99%. However, combined pollution showed inhibitory effect on the removal of NH₃-N and TN. This effect became strong with the increased addition of the Cu and SMZ. The average NH₃-N removal rate of 5 groups were 81.75%, 87.59%, 79.50%, 74.45% and 65.41%, and the average TP removal rate of 5 groups were 81.59%, 87.63%, 80.82%, 74.15% and 67.56%, respectively. When Cu and SMZ were added at the same time, the dry weight of plant foot end were 22.22%, 30.58% and 30.64%, which were lower than that of group A. Combined pollution of Cu and SMZ had a negative effect on canna as well as a selective effect on microorganisms. It implies that the combined pollution may affect the removal of NH₃-N and TN by affecting plant functions and microbial community structure.