The present invention provides a method and equipment for breeding seaweed, wherein the method includes following steps: breeding seaweed in a breeding tank draining the water from the breeding tank when the water temperature was over a target temperature until the draining water meets a water quantity and stop draining and filling a Liquefied Natural Gas (LNG) cold drainage in the breeding tank.本發明提供一種海水藻類養殖方法與設備,其中海水養殖的方法的步驟包含:養殖水池中培育一藻類,當養殖水池水溫超過一目標溫度時排水,排出一固定水量後停止,再補入液化天然氣(Liquefied Natural Gas,LNG)冷排水。100‧‧‧養殖水池101‧‧‧篩網200‧‧‧排水管300‧‧‧補水管301‧‧‧液化天然氣接收站400‧‧‧曝氣系統401‧‧‧曝氣管402‧‧‧攪拌器