[en] Highlights: • Via solvent–thermal and pyrolysis method, VO_2 (M) powder was synthesized in air. • Aiding by grinding, VO_2 (M) nanoparticles with the size of 22 nm were obtained. • The VO_2 films show great thermochromic properties with T_l_u_m = 62.1% and ΔT_s_o_l = 12.4%. • The haze is down to 1.9%, which is superior with films prepared by other methods. - Abstract: In this paper, high crystallinity and pure phase VO_2 (M) powder is synthesized by a novel and facile method. Aiding by additional manual grinding and etching process, 22 nm high-quality VO_2 (M) nanoparticles can be obtained. The structure and properties of the VO_2 (M) particles were characterized by X-ray diffraction analysis, transmission electron microscopy, differential scanning calorimetry and UV–vis–NIR spectrophotometer. After mixing VO_2 (M) nanoparticles with transparent polymer, thin films prepared by grinded VO_2 nanoparticles show excellent thermochromic properties. The solar modulation ability is up to 12.4% with luminous transmittance of 62.7%. Moreover, The haze of films prepared by grinded VO_2 (M) nanoparticles is down to 1.9%, which is far less than that of films prepared by original VO_2 (Haze = 8.5%) and etched VO_2 particles (Haze = 4.6%). Dramatical improvement of thermochromic property and definition indicate that it is a promising method to prepare large-scale VO_2 nanoparticles and cost-effective smart window