With the acceleration of the urbanization process of islands, the contradiction between the development and construction of islands and the ecological safety has become increasingly prominent. It is of great significance to promote the coordinated development of the social, economic, and ecological environment of Pingtan Island by objectively evaluating the dynamic changes and the driving forces of the ecological conditions in the development and construction of Pingtan Island. We selected 2001 as the ecological security status evaluation benchmark year. In addition, natural and socio-economic indexes from 2005 to 2015 were selected to construct the Driving forces-Pressure-State-Impact-Responses (SPSIR) evaluation index system for ecological security assessment of Pingtan Island. Using the comprehensive index method, it was observed that the driving factors and impact factors were relatively stable in the evaluation years. The dynamic trends of the pressure and state factors were similar. The dynamic changes in the response factors were relatively stable before the establishment of the comprehensive test area in 2009, but the fluctuation was most obvious from 2009 to 2012. Response factors, pressure factors, and state factors have a significant impact on the ecological security index. Response factors, taken together, was the key factor impacting ecological security index. The ecological security status of Pingtan Island is on the rise, but the ecological security situation was relatively stable in 2001 and 2005 to 2009. Since the establishment of the comprehensive experimentation area, the ecological security index has risen the maximum, especially during the period from 2009 to 2011. From 2011, the ecological security index reached 0.7612, which was a good threshold compared to the ecological security situation of 2010 and then showed a slight decline at a smooth state from 2012 to 2015. Correlation coefficients between the state index, driving force index, response index, and safety index were higher, and the response index was greater than the correlation coefficient of the pressure index. Through principal component analysis and path analysis, it was found that the principal component scores in 2011 and 2015 were the highest, with 1.5277 and 1.1974, respectively. The response factors play a crucial role in the ecological security of Pingtan Island. Among these, Transportation investment ratio, Health and social security investment ratio, Public facility investment ratiohave direct and indirect impacts on the ecological security of Pingtan Island. These results support the empirical case and relevance of the theoretical system of island environmental assessment, and provide a reference for the ecological security assessment of the domestic island urbanization process.