Using self-determined design of SPJ-40 experimental twin-screw extruder to extrude the banana peel is investigated in this study. Results revealed that the best extrusion conditions were: banana peel and starch at rate of 2:8, feed moisture at 16%, screw speed at 268r/min, extrusion temperature at 150°C, and feeding rate at 20r/min. The structures of the products were determined after the extrusion. The electron microscopy showed that the structure of the starch powders and fibers had been greatly damaged, leading to the great increasing of surface area of processed products. Compared to the raw material, the crystallinity of products was down to 13.06% from 19.85%, but soluble dietary fiber was increased by 30.3 percent. The final product tastes delicate with palatable aroma. Overall, this extrusion technology for processing banana peel has bright prospect in application.