Maritime industry is affected by outside factors significantly due its derivative demand characteristics. Exchange rate, international oil and commodity price, economic fluctuation all affect the demand in the maritime industry directly and the changes are applied immediately. However, the supply side can not react to these changes immediately and due to this uniqueness, maritime industry repeats the boom-bust cycle. Foreign exchange crisis that started since mid 2008 has shrunk the physical market resulting in long term recession of the industry. This led the bankruptcy of domestic shipping companies and the shipbuilding industry is also suffering from depression as a result. Maritime industry requires a large scale of funds and a high manpower. Therefore the government itself needs to operate early warning system in order to monitor the market and notice the upcoming risks by setting up a system to prepare for the situations. Currently, Republic of Korea is operating various early warning systems in markets such as, but not limited to, grain, commodity, finance, real estate and employment. Systems in these markets are inspected for the accuracy periodically and improved to increase the risk predictability. In this research, signal approach, which can be easily applied to the industries that has various related activities and also currently used in other areas, is used to establish early warning system. Overall leading index is composed of crisis index that is based on BDI and various leading indexes such as finance, economy, shipping and the others. As a result of computing overall leading index which is early warning system in maritime through signal approach, the index showed a high correlation coefficient with actual maritime risk index by difference of 4 months. Also, the result was highly accurate with overall leading index’s QPS at 0.37. Therefore, overall leading index which has been developed through this research seems suitable to be used as early warning index.