Use level of offshore municipal solid waste landfill site (OMSWL) has been low. To utilize OMSWLs intelligently, installation of piles through natural barrier as clay layer will be required. But leakage of wastes or polluted water is anticipated if installation of piles which penetrate through the waste layer and the natural clay barrier layer beneath it. In this research, firstly, summaries of barrier performance required to OMSWL and the states and issues on the use of abolished MSWLs were made. Secondly, effects of leakage of wastes and polluted water during installing piles and long term after installation of piles were studied. From this study, leakage effect can be minimized by appropriate treatment during pile installation. Finally, items to be considered when constructing piles in field were extracted and summarized.