The invention discloses an orderly fruit putting system for a slender melon picking robot, and relates to the field of agricultural robots. The system is composed of a fruit box flexible inclining mechanism, a flexible lifting mechanism and a mechanical arm translation mechanism. By means of an elastic translating follower, a fruit box is made to incline back on to a picking area, and the fruit box is made to rise and fall. When operation is conducted, a mechanical arm clamps slender melons to reach the portion above the fruit box and then inclines downwards to move to the lifting end of the fruit box, and then the slender melons are made to lie down in a groove of the fruit box. The fruit box is gradually laid flat and fallen off along with increase of slender melons inside the fruit box, falling of the fruit box and the stack height of the slender melons inside the fruit box mutually compensate, it is guaranteed that the mechanical arm puts fruits repeatedly and orderly according to the fixed position and action, and the phenomenon that after the stack height is increased, the slender melons fall out of the box is prevented. Accordingly, the orderly, full-box and lossless fruit putting of the slender melons is achieved only through matching of elastic translating follower-based flexible fruit box inclination and lifting, the structure and control are simple, the fruit putting operation efficiency is greatly improved, and the back-and-forth fruit discharging frequency of the picking robot is effectively decreased.