Abstract: The present invention refers to bast fibers for plastics reinforcement and preparation method thereof. The bast fibers are composed of the following components by weight ratio; 100 pts.wt. chopped bast fibers, 0.1˜100 pts.wt. bast fiber treating agent, 1˜10 pts.wt. Functional Polyolefin wax, 0.1˜10 pts.wt. coupling agent and 0.1˜0.5 pts.wt. antioxidant. The method includes the steps of: firstly, cut chopped bast fibers and soak them in sodium hydroxide solution, agitate the mixture, after rinse and drying of water, soak the fibers in the aqueous solution of bast fiber treating agent, then dry them and obtain surface-treated chopped bast fibers; secondly, add in order the chopped fibers, the coupling agent, the Functional Polyolefin wax and the antioxidant to a preheated kneader, agitate the mixture and thus obtain bast fibers for plastics reinforcement.