The green beans used for quick freezing shall be fresh and tender, bright green in color, uniform, slender, free of spots, diseases and pests and other pollution. All pests, abrasions and deformities shall be removed; For varieties without lateral reinforcement, the tips at both ends shall be cut off; For varieties with side bars, remove the side bars and cut off the tips at both ends. Then wash the green beans in clean water for 3 ~ 4 times.