Abstract: The serious waters pollution are caused by accidents that take place in petroleum production, processing, storage and marine transportation and the oil-bearing water running into the sea. The article makes an analysis of the harmness of two pollution sources, centers, in particular, on briefing the preventive measures against the pollution source as running into the sea in hige flow-rate, in another word, the floatingoil recovery equipment and the present technical state. In view of the fact that cofferdam is the common way ned by all the countries in the world to enclose the overflowing oil which is then revovered with the unrecovered dealt with deoiling agent, the article explains in detail the function, principle and structure of oil cofferdam, the selection and a few types of cofferdams frequntly used in the world, and expounds the floating oil recovery principle and equipment that are created by making use of the difference of specific weight beween oil and water, the absorbability of oil to other substances and the characteristics of synthetic fibre such as affinity to oil and repulsion to water. It gives a summary of the measures taken all over the world to prevent ail overflowing occurances, the present research state, the rules and regulations for conservation of enviroment, mentions in particular some advenced countries such as the United States, Japan, etc. Considering that China is just beginning in this field, what should be done now is to completc the cnviroment conserve regulations, to do much more propaganda, develop technique with great effort and get down lo researel into oil recovery technigue and the necessary equipment concerned.