The effects of single and compound fly ash and plastic waste on the mechanics and durability of concrete modified with fly ash and polypropylene particles are studied. The results show that the appropriate amount of fly ash has no obvious effect on the mechanical properties of concrete at late age, and the appropriate amount of fly ash can improve the durability of concrete at late age. Single-doped polypropylene plastic particles reduce the mechanical properties and durability of concrete. The mechanical properties and durability of concrete in the late stage can be effectively improved by adding fly ash and polypropylene particles in appropriate amount. When the mass ratio of fly ash and polypropylene particles is 1∶1, the mechanical properties and durability of concrete are better under the condition that the total content is 30%.