Traditionally tonnage tax is a tax which customs imposes on a vessel which passes through the border. Modern tonnage tax is in essence a corporate tax based on the tonnage of the vessel. Major shipping countries in the world have carried out modern tonnage tax system. The present tonnage tax in china has caused certain obstacles to the development of shipping enterprises. To promote modern tonnage tax in our country is of great importatnce to the development of China’s trade and shipping. Thus the customs，as an enforcement agency which is entitled to expressing constructive opinion，shall coordinate with tax authorities to form a sound shipping tax system and improve the efficiency of enforcement.