The invention relates to an automatic male and female sorting device for judging sexes of cocoons by fluorescent color and belongs to the technical field of textile and silk producing. The device comprises a cocoon inlet channel and an adjusting and controlling circuit; the side wall of the cocoon inlet channel is provided with a light sensor, and the lower end of the cocoon inlet channel faces an activation cavity; the side wall of the activation cavity is provided with an ultraviolet filter, and the bottom of the activation cavity is provided with a yellow filter; the outer side of the ultraviolet filter is provided with an ultraviolet source, and a photosensitive element is arranged below the yellow filter; the two sides above the large end of the activation cavity form a cocoon outletchannel, the upper wall of the cocoon outlet channel is provided with an air pipe, and an air outlet of the air pipe faces the activation cavity; the output end of the light sensor is connected with the trigger end of the adjusting and controlling circuit, the output end of the photosensitive element is connected with the signal input end of the adjusting and controlling circuit, and two controlling and outputting ends of the adjusting and controlling circuit are respectively connected with two electromagnetic valves. According to scientific sorting principle, judging sexes of cocoons can be completed automatically with high accuracy and efficiency, thus creating conditions for ensuring sorting quality and reducing sorting cost and laying foundation for producing high-quality raw silk later.