The utility model discloses a flexible automatic production line for fasteners. The utility model relates to the technical field of production lines, in particular to a full-automatic double-spindle marking machine which comprises a plurality of double-spindle lathes, conveying equipment, vibration feeding equipment, a marking detection unit and a closing-in unit, the double-spindle lathes are arranged in parallel at intervals, a feeding platform is arranged at one end of each double-spindle lathe, and a lathe discharging opening is formed in the other end of each double-spindle lathe; whereinthe conveying equipment is parallel to the arrangement direction of the double-spindle lathe, is arranged close to a discharging opening of the lathe and extends to a feeding opening of the vibrationfeeding equipment; the label making detection unit is arranged at a discharging opening of the vibration feeding equipment; and the closing-in unit is arranged close to the label making detection unit. The production line is high in flexibility and suitable for production of various fasteners in small batches, the production efficiency, the detection speed and the product quality are improved, manual labor is reduced, and the production cost is reduced.