The preparation of brine is basically to absorb and enrich sea salt by beach sand, and then to obtain concentrated brine by tidal leaching or artificial impregnation. Su Song's Compendium of Materia Medica in the Northern Song Dynasty had a very detailed record, saying, "Yu Haibin dug a pit, covered it with bamboo, and then covered it with Mao Peng, covering it with sand. Every time the tide washes the sand, the brine is drenched in the pit ... because the sea brine is injected into the plate and fried, it will be instant. " . In the introduction of Hailing Salt Supervision Station in Haimen County, Tongzhou, Taiping Ji, a music history of the Song Dynasty, recorded the method of scraping sand and soaking brine, but instead of washing sand with tidal water, the salt sand was soaked by seawater artificially scooped into the pit and canal.