The invention discloses a novel composite lean 
iron ore pre-concentration technology and a production 
system thereof, and belongs to the technical field of ore concentration. The novel composite lean 
iron ore pre-concentration technology includes the steps that composite lean 
iron ore is crushed; the crushed products are smashed to be phi 3 mm through a high-pressure roller milling screen fully-closed superfine crushing technology; a wet low-intensity 
magnetic separation and wet high-intensity 
magnetic separation combined technology is carried out; concentrate of a low-intensity 
magnetic separation machine and concentration of a high-intensity magnetic separation 
machine are mixed and then later ball milling grading starts; 
tailings of the high-intensity magnetic separation 
machine enters a 
linear vibration screen II for 
dehydration. The production 
system of the novel composite lean iron ore pre-concentration technology comprises a high-pressure roller 
grinding machine, a wet efficient beating machine, a 
linear vibration screen I, the low-intensity magnetic separation machine, the high-intensity magnetic separation machine and the 
linear vibration screen II which are sequentially distributed on a production 
assembly line according to the process sequence. By means of the technology and the 
system, a large amount of qualified 
tailings can be abandoned before the composite lean iron ore is ground, the 
grinding amount is lowered, and the aims that more tailing is crushed, little tailing is ground and the tailing is abandoned earlier are achieved.