The invention provides a crop straw picking device, which is characterized in that a bearing seat, a picking shaft and a belt wheel are connected between a machine frame and a cam groove, a disc frame is connected onto the picking shaft, an elastic tooth rod is connected onto the disc frame, and an elastic tooth support seat, a picking elastic tooth, a groove wheel shaft, a groove wheel arm and a groove wheel bearing are connected onto the elastic tooth rod. After the belt wheel is driven to rotate by motive power, the picking shaft, the disc frame and the elastic tooth rod are driven to rotate, in the rotating process, the elastic tooth rod is driven to rotate in a certain angle range by the rotation of the groove wheel bearing according to a track of the cam groove, the elastic tooth support seat and the picking elastic tooth are driven to swing, the picking elastic tooth starts to pick straws when swinging to a position near the ground, then, the straws are upwards conveyed, when the straws are conveyed to the upper side, the picking elastic tooth is retracted, and the operation process of picking and conveying the straws is completed.