Abstract: Abstract: Bananas occupy an extremely important position in the world of fruit trade; it is the most important fruit in tropical and subtropical areas. China is one of the world's largest producers of bananas, and bananas have become an agricultural pillar industry in China's subtropical regions. However, the banana stalks are a major agricultural waste. According to the Food and Agriculture Organization (FAO), in 2010, 24 million tons of annual output of waste is banana straw in China. If such a large amount of waste straw is not handled in time, it would seriously pollute the environment and affect the renewal of the banana plantation. Because banana stalks are thick with a high level of moisture and other issues, there are less mature mechanical equipments for banana stalks treatment at the present. There are usually two main types of banana stalk treatment: one is to cut down and pile the stalk in the fields by laborers, and then let it rot; the other one is a centrally smash processing with machines. This kind of machine can achieve a certain crushing effect, but, due to the characteristics of its own design, can't achieve the field operations, and thus brings great inconvenience for the laborers. In view of above situations, according to craft about the banana stalks' crushing and returning in the field, this study designed a feeding type vertical shaft flail extracting machine for banana stalks' crushing and returning, and expounded the machine's overall configuration and the main components of the structure, and determined the key parameters of the optimal value through the analysis of the relationship between components and performance test. The machine could work directly in the field under the tractor traction, for the stalks to achieve down, tackle, grab, feed, crush and return. Field experiments showed that: with the speed for forwarding at 2.16 - 3.60 km/h, for the feed roller at 127.39 r/min, and for the vertical sling knife at 1080 r/min, this machine could achieve a qualification rate of straw smashing of 94.9%, field coverage of 88.61%, stem stubble height of 30 - 35 mm, energy consumption of 4.625 kg/h, and working efficiency of 0.39 hm2/h. This machine was easy to operate and its crushing effect was satisfactory. Its successful implementation could not only greatly improve the production efficiency, and solve the problem of large-scale banana cultivation facing massive stalks processing, but also prevent the pollution of the environment and had important economic and ecological benefits.