The lithium adsorption tests using the granulated absorbent have been done on the bench scale model. On the basis of the adsorption tests, a conceptual design on extraction system of lithium from sea water is presented in this study. The extraction system consists of a barge with absorbent bed tanks and a pusher boat. In the proposed system, sea water flows into the absorbent bed tanks from suction valves on the inner bottom of the barge, then passes through the piled absorbent and is finally discharged out of the tank by drain pumps. In addition, numerical simulations for the extraction system are carried out under the assuming operation circumstances. A feasible assessment on the extraction system is also made in this paper.