The invention relates to a device for preventing and controlling snails. The device comprises a baffle for preventing the snails from entering a protected matted bed, and a collector for collecting the snails retaining on the baffle. The baffle comprises a vertically arranged baffle body, a top flanged edge which is arranged on the top of the baffle body and is extended along the direction deviating from the protected matted bed, and an anti-crossing flanged edge which is arranged on the outside of the top flanged edge and is extended downwardly. Because of the adoption of the technical proposal, the device prevents the peripheral snails from entering the matted bed and endangering the crops; and the snails are detained in the flanged edges of the baffle and are captured conveniently. The snail collector simplifies and facilitates the snail capturing process without omission. The device purely adopts a physical principle. According to the activity rule that the snails only have a food taking tendency without intelligence, the device can separate the snails out of the planting range of the cash crops, and collect and kill the snails, thereby making the planted crops be truly green or nuisance free.