The invention discloses a system and a method for deeply treating brown alga chemical engineering waste calcium water through a double-membrane technology. The system for deeply treating brown alga chemical engineering waste calcium water through the double-membrane technology is characterized in that a brown alga chemical engineering waste calcium water pipeline 8 is sequentially connected with a coagulation-air flotation treatment tank 1, a ceramic membrane module 2, an activated carbon tank 3 and a reverse osmosis membrane module 4, and the reverse osmosis membrane module 4 is connected with a production water pipe 9; and the ceramic membrane module 2 is connected with a settlement tank 6 through a pipeline, and the settlement tank 6 is connected with an oxidation reactor 7 and the coagulation-air flotation treatment tank 1 through a pipeline. The ceramic membrane module is used to pre-treat the waste calcium water, so the process treatment step is simplified; and the ceramic membrane module occupies a small area and has a high sewage treatment efficiency. The pretreatment using a ceramic ultrafiltration membrane system significantly reduces the pollution of a reverse osmosis membrane, reduces the cost of the pretreatment process and realizes easy technology amplification.