Wetlands play an important role in maintaining ecological balance and promoting the development of surrounding economy. Chemical pollutants in industrial wastewater cause serious damage to the wetland ecosystem. For this, taking the polycyclic aromatic hydrocarbons (PAHs), one typical chemical organic pollutant in industrial wastewater as examples, this paper studies the effects of PAH on plants and microorganisms in wetlands. Then, the experimental simulation was conducted to study the degradation and absorption effects of wetland soil sediments and wetland plant (Spartina alterniflora) on PAHs, and also analyse the effects of PAHs on total biomass and microbial active enzymes in wetlands. The results show that the wetland ecosystem has significant absorption and degradation effects on chemical pollutants. The average removal rate of PHE is 26%, and the average removal rate of PYR is 20%; the content of PHE and PYR in leaves of Spartina alterniflora (S. alterniflora) is much smaller than that of root system, indicating that the root system of S. alterniflora is the main part of absorbing PAHs. PAHs pollution will cause serious damage to the distribution and content of microorganisms in the wetland. PHE causes the microbial content in the leaves of S. alterniflora to decrease by more than 35%, while PYR causes it to decrease by more than 26%. The plant-microbial combined treatment system in the wetland system can resist the harmful effects of chemical pollutants to a certain extent, and the bacteria in the plant roots are more sensitive to the response of chemical pollutants. This can provide a new research idea for the microbe-plant joint degradation of chemical pollutants in wetland ecosystems.