Abstract: In consideration of the fact that the production conditions of high inclination-angle fully mechanized caving face is complicated，coal winning machine produces a great quantity of dust，and the caving coal dust is easy to float in the sky.In combination of field measurement and experimental analysis，a research on dust producing quantity and particle size distribution was conducted on coal mining machine，and the floating dust amount and fall dust amount of coal winning machine are calculated by measuring in caving face.The suppression ejector systems in high inclination-angle fully mechanized caving face is designed，which can prevent dust from floating in the sky，strengthen the spray dusting and dust flow control.And then，it was applied to caving faces.The results showed that about half of dust produced by coal machine is floating dust with the dust median diameter of 8.22 μm，and the respirable dust accounted for 44.5% of all the dust.It should be focused on.The respirable dust collection efficiency with coal mining machine suppression ejector systems is improved from 49.5% to 65.3%.In combination of ejector spray filter and nozzle installation in hydraulic support，the whole dust collection efficiency is improved from 69.4% to 85.7%.This technique may provide a reference for the dust prevention in caving coal location of high inclination-angle fully mechanized caving face.

Key words: Fully mechanized caving face, Dust, Particle size distribution, Caving coal, Dust removal