The composite properties of polymer composites for municipal sewer pipes are studied. Firstly, the research background is introduced, and then the definition and classification of polymer grouting materials are expounded. The environmental stability and safety properties of polymer composites are analyzed, and the conclusions are drawn as follows: first, polymer composites are safe and non-toxic, and even if they are buried underground for a long time, they will not be harmful to the environment because of the long-term immersion of groundwater and the release of toxic and harmful substances; second, polymer composites will not lose their stability and thus affects their effectiveness due to the chemical corrosion of normal ground environment.