The marine economy is a new economic growth target under the new paradigms of China's economy. Since 2011, China has established successive marine economy demonstration zones. However, there is no conclusion yet drawn as to the effect of the marine economy demonstration zones. In this paper, the earliest Shandong Peninsula Blue Economic Zone is set as our research object, the GRAM-DID model is used to evaluate the net effect of the establishment of the Blue Economic Zone, and the marine economy of Shandong Province input-output model is compiled to estimate the economic growth effects of other industries induced thereby, which makes the assessment of the net effect more accurate and comprehensive. The results show that the net economic growth arising from establishment of the Blue Economic Zone is 304204.7 million yuan, which induces significant economic growth in the circulation of goods and services and the manufacturing sector.