The invention discloses a sinking-prevention structural body of a well peripheral composite material. The structural body comprises a base and a well lid seat. The base is a table body, wherein the center of the table body is provided with a through hole matched with the well lid, and the base is embedded on the roadbed on the periphery of a well hole of an inspection well. The well lid seat is arranged on the base and is flushed with the road surface. The base is made of concrete composite materials and comprises, by weight, 300 parts to 500 parts of cement, 30 parts to 50 parts of expanding agents, 1500 parts to 2000 parts of aggregate and 8 parts to 10 parts of water reducing agents. According to the sinking-prevention structural body of the well peripheral composite material, the load diffusion area is increased so as to obviously reduce shaft stress, and the phenomena of well periphery sinking and the like caused by damage of a brick body of the shaft are avoided.