Abstract: Micro-nano particles of plant lignocelluloses were prepared and characterized in present study. The poplar wood were milled to be powders and then dissolved in DMSO/LiCl. The dissolved powders were regenerated to be stable suspensions in the water and dried to be micro-nano particles with spray drying under mild conditions. The factors affecting the preparation processes were investigated and optimized. The results showed that the dissolution ratio reached to maximum 55.6% when the temperature was 70℃, the solid and liquid mass ratio was 3:100, the mass ratio of LiCl in DMSO was 8%. The suspension particle size reached the minimum 85 nm when the rotational speed of the high speed dispersion machine was 2 000 r/min, the mass ratio of CMC-Na and wood was 1%. The raw materials and products were characterized by FT-IR, Malvern Zetasizer instrument, SEM, TEM and TG, respectively. It was revealed that micro-nano particles of the plant fiber made by this method possessed a higher specific surface area and they could be used as new fine chemical nano-materials.