The theories of DEA were introduced and the method was applied to the marine fisheries in China. Firstly, the result showed that the ship sizes were too small which affected the increase of the fishing capacity and the capacity utilization, though there were enough ships in the Chinese distant water fisheries. Secondly, the capacity utilization of the relative provinces is in two extremes. Among these provinces, the rates of Liaoning, Jiangsu, Shandong and Guangdong are the highest and the others may increase their catch much by only raising their production efficiency with no more investment. The analyses of the stow nets' fishing in Zhoushan showed that the fishing capacity will not change when an input factor changes at the same rate in different units. So the DEA method can make comprehensive analyses of the variable investing, the fixed investing and the catch in fishing to determine the maximum output in multi investments. This method is also able to deal with not only a lot but also a little of data, and the results of its application to marine fishing are satisfactory.