Abstract: This is an article in the field of mineral processing engineering. Tourmaline has been widely used for its spontaneous polarity, pyroelectric effect, far-infrared radiation and negative-ion release effect. In order to increase its stability in water-based coatings and improve its performance in water-based coatings, in this work, the surface modification of tourmaline with carboxylated nanolocellulose (C-CNF) was studied and optimized. The test results show that the performance of modified tourmaline was optimal while the addition of C-CNF was 2 g, solid-to-liquid ratio 1:5, and reacted 2h at 50 ℃, its turbidity reached 1361 ntu, contact angle to 53^o. It was found that C-CNF was successfully grafted to the tourmaline surface by means of characterization of the modified tourmaline, and the dispersion of the modified tourmaline in the aqueous medium was better improved.