A weeding device for crops having a seedling avoidance function includes a rack connected to a weeding machine. A hydraulic pump and two hydraulic cylinders are mounted to the rack. Bottom ends of each of the two hydraulic cylinders are provided with a vertically arranged support rod. An inter-row weeder is mounted to a bottom end of each of the two support rods. A slider configured to reciprocate in a horizontal direction is positioned on two slide rails that are mounted to the rack. An inter-plant weeder is mounted to a bottom side of the slider. A plurality of weeder blades are arranged side by side on the inter-plant weeder. At the weeding position, an arrangement direction of weeder blades is perpendicular to an advancing direction, and at the weed avoidance position, the arrangement direction of the weeder blades is parallel to the advancing direction, thereby avoiding crops.