The invention relates to the technical field of 
sewage treatment, and discloses an anti-
sewage backflow device for urban inspection wells based on the principle of 
electromagnetic induction, which includes a well wall and a slide rail. The top of the well wall is movably connected with an inspection well cover.  The water inlet 
pipe is movably connected, the inside of the well wall is movably connected with a sliding 
assembly, the outside of the sliding 
assembly is movably connected with an electromagnetic 
assembly, the inside of the well wall is fixedly connected with a 
magnet one, the inside of the well wall is movably connected with a baffle, and the inside of the baffle is  The second 
magnet is fixedly connected; through the interaction between the well wall, inspection well cover, water inlet 
pipe, sliding assembly, electromagnetic assembly, negative pole, positive pole, and 
copper rod, it can achieve anti-
backflow after triggering when 
sewage backflow occurs  The structure operates, which provides prerequisites for the start of anti-backflow, and this design will only start when the sewage is poured back close to the manhole cover, which is more in line with the actual situation.