The invention discloses a preparation method of enhanced bean vermicelli. The preparation method comprises the following steps: soaking peas twice and grinding the soaked peas into thick liquid; filtering bean milk to remove dregs, and precipitating twice to obtain pure pea powder; uniformly mixing the pure pea powder in warm water, adding cellulose nanocrystals and nano-chitosan, rushing by hot water and adding a saline solution to obtain vermicelli dough; vacuumizing the vermicelli dough through a vacuum dough kneading machine, conveying to a dipping machine through a spiral conveyor to form bean vermicelli; discharging the bean vermicelli out of a pan when the bean vermicelli is in a slight boiling state and cooling through cold water; then naturally cooling; implementing processes of freezing the bean vermicelli through a refrigerator, spraying warm water for unfreezing, draining off the bean vermicelli, and drying the bean vermicelli by a dryer; and inspecting, packaging, and introducing a finished product to the market. The enhanced bean vermicelli produced by adopting the method disclosed by the invention is convenient to eat, and keeps the original quality of peas; the bean vermicelli is free from any chemical additive and antiseptic, and can increase the contents of dietary fibers for the human body after long-term eating; and therefore, the enhanced bean vermicelli is a natural health food.