Tube-grafting is a kind of vegetable seedling grafting with closed or open tube. Compared with using grafting clips, tube has the features of cheepness, well grafting wound moisturizing and so on. Grafting with tubes can not only reduce the grafting production cost, but also can improve the survival rate of grafting seedlings. In today’s tube-grafting situation, it basically relies on manual grafting operation at home and abroad. There is much significance to develop a tube-grafting machine. The most important and key part of a tube-grafting machine is the tube-providing part, which provides the tube one-by-one and matches the pace of grafting processing. To provide tubes for a grafting machine based on tube-grafting method, a special tube-outputting mechanism was designed. The mechanism consisted of a vibration sorting-tube device, a tube duct and a tube one-by-one delivery unit. Experiments were conducted in laboratory, the results showed that at the voltage of 185 V, the variation coefficient of tube-outputting by the vibration sorting-tube device reached the lowest value of 61.75%. In this situation, the tubes were put out steadily. And the success rate of tube delivery by tube one-by-one delivery unit was 100%. The tube one-by-one delivery unit worked perfectly in the experiment. And the mechanism was available in situations of variable tube numbers. It can provide tube one-by-one with pace of grafting and it is useful for future development of grafting machines based on tube-grafting method.