The invention relates to a lean magnetite high-pressure rolling-dry pre-separation-fine screening-regrinding process. The process is characterized by comprising the following steps that after lean magnetite raw ore is subjected to coarse crushing and middle crushing operation, the product particle size reaches 40-0 mm; middle-crushed products are fed into a high-pressure rolling-dry magnetic separator for separation, then dry separation tailings are fed into a tailing recovery weak magnetic machine, and iron minerals in the dry separation tailings are recovered; concentrate recovered by the tailing recovery weak magnetic machine and dry separation concentrate are combined to be fed into a regrinding machine for regrinding, reground products are subjected to separation of a first stage dewatering tank and a first stage weak magnetic separator, and then concentrate of the first stage weak magnetic separator is fed into first stage fine screening operation; and fine screening oversize products return to the regrinding machine for regrinding, fine screening undersize products are final concentrate, and the grade is 67.3%-67.8%. According to the lean magnetite high-pressure rolling-dry pre-separation-fine screening-regrinding process, novel high-pressure rolling-dry separation magnetic separator ore separation equipment is adopted, fine crushing operation, two stages of ore grinding and one stage of magnetic separation operation are replaced, ore separation cost can be reduced substantially while the process course is simplified, and economic benefit is significant.