Abstract: To understand the efficiency and optimization method of purifying fine particles with wet chord grid water film,the experimental dust with an average particle size of about 10 μm was prepared. The pressure nozzle atomiza- tion characteristics experiment and wet chord grid water film dust removal characteristics experiment were conducted based on the self-built experimental platform. The variable relationship between the atomization parameters of pres- sure nozzle and dust removal efficiency was studied. The feasibility of increasing the water supply pressure and the chord grid surface hydrophobic modification to improve the efficiency of wet chord grid water film purifying fine particles was verified. The results show that the spray flow rate of the three kinds of pressure nozzles increases with the increase of water supply pressure,and the atomized particle size decreases as the water supply pressure increases. Un- der the experimental conditions that the air duct velocity is 3 m / s,the atomization effect of the hollow conical nozzle is better than that of the square conical and solid conical nozzles,the water supply pressure increases from 0.3 MPa to 1.3 MPa,the spray flow rate and atomization angle increase by 1.19 L and 5.2°,respectively,and the atomization par- ticle size decreases by 44.1 μm. The dust removal efficiency of wet chord grid water film dedusting is positively corre- lated with the spray flow rate of the pressure nozzles,and negatively correlated with the atomized particle size. The hol- low cone has the best dedusting effect. The dedusting efficiency of the wet chord grid under five water supply pres- sure conditions is 67.16%,68.56%,70.29%,73.80% and 75.89%,respectively. The resistance loss of wet chord grid water film dust removal section increases linearly with the increase of the air duct velocity,and the resistance coeffi- cient is 13.14. The effect of optimizing the dust removal efficiency by increasing the water supply pressure is not signif- icant. The water supply pressure increases from 0.7 MPa to 1.3 MPa,the dust removal efficiency of the wet chord grid water film increases by 6.63%,and the highest dust dedusting is 81.57%. With the increase of spray time,the water film filling ratio of chord grid section increases sharply at first,then decreases slowly,and finally tends to be stable. Af- ter the hydrophobic modification of the chord grid surface,the water film filling ratio of the chord grid section increases from 66% to 78%,the efficiency of the wet chord grid water film purifying fine dust is improved. Under the six experi- mental conditions of the water supply pressure,the total dust removal efficiency is 80.27%,84.53%,85.38%,87.00%, 88.45% and 90.58%,respectively. The dust removal efficiency of respirable dust with aerodynamic equivalent diame- ters of 5,7.07 and 10 μm can reach 82.68%,83.16% and 86.31%,respectively.