The invention relates to a dry-screening pre-selecting waste-discarding mineral separation technology for monohydrallite with the low alumina silica ratio. The process comprises the steps of directlyscreening raw ore through a bar screen so as to obtain plus sieve lump ore and minus sieve powder ore, carrying out first-section dry-screening and waste-discarding on the minus sieve powder ore through a first vibrating screen, and producing (0 to 10mm) minus sieve waste ore and plus sieve ore; and coarsely crushing the plus sieve lump ore, combining the crushed plus sieve lump ore and the plus sieve ore of the first vibrating screen, carrying out intermediate crushing, carrying out second-section dry-screening and waste-discarding on the ore subjected to intermediate crushing through a second vibrating screen, and producing (0 to 10mm) minus sieve waste rock and plus sieve ore, wherein the plus sieve ore is a final DSO product. According to the process provided by the invention, after the raw ore is subjected to two sections of dry-screening pre-selecting waste-discarding selection, the discarded waste rock yield reaches up to 30 percent, the alumina silica ratio of ground monohydrallite is improved by about 10 percent, the mineral separation and monohydrallite smelting cost can be reduced, the monohydrallite ore with the low alumina silica ratio is favorably developed and utilized, and the resource utilization rate is improved.