The present invention discloses a fibrilia for plastic reinforcing and a method for manufacturing the same. The fibrilia contains the following components in part by weight: 100 chopped fibrilias, 0.1 to 100 fibrilia agents, 1 to 10 functional polyolefins, 0.1 to 10 coupling agents and 0.1 to 0.5 antioxygens. The method comprises the steps of: cutting off the chopped fibrilias; immersing the cut chopped fibrilias into a sodium hydroxide solution and stirring the solution; washing out the chopped fibrilias after taking out them from the solution; drying the obtained chopped fibrilias; then immersing the dried chopped fibrilias into solution with the fibrilia agents; drying to obtain the chopped fibrilias with surface treatment; adding the chopped fibrilias, the coupling agents, the functional polyolefins and the antioxygens into a preheated kneader in order; and stirring to obtain the fibrilia for plastic reinforcing. The chopped fibrilias manufactured by the present invention has goodcolor, good rigidity, good heat resistance, and good compatibility with the plastic, thus the chopped fibrilias can be used for manufacturing chopped fibrilias/plastic composite materials with high performance, and can play a reinforcing role in plastic substrates.