The research on the connotation and the evaluation index system of low carbon competitiveness in the ocean economic zone is not comprehensive, it ignores some factors, such as, spatial structure, fairness, regional cooperation, urbanization, system innovation. This paper first puts forward the connotation and the benefit-potential evaluation index system of the ocean economic zone, and then uses the index system to evaluate low carbon competitiveness of Shandong peninsular blue economic zone by using the empirical method.Low carbon competitiveness in the ocean economic zone means a competitive advantage that can optimize economic benefit, social benefit, and the ecological benefit of the zone, and the competitive advantage is formed by the synergistic effect, cooperation, rational distribution of the component elements of the zone and by the interaction in low carbon development of the ocean economic zone and external region. In the process, the principle is 6R of low carbon development, and the basis is regional interest coordination mechanisms.The results show that: there is great difference in urban low carbon competitiveness of Shandong peninsular blue economic zone because the highest value (0.77526) and the lowest value (-0.57536) is in Qingdao and Weifang respectively, and the difference is 1.35062; Qingdao is the first order low carbon development pole of the zone, Yantai (0.25704) and Dongying (-0.04371) are secondary low carbon development pole; the zone has point-axis spatial structure characteristics; there is a positive correlation between low carbon competitiveness of the ocean economic zone and regional economic developing stage; the differences in spatial structure characteristics of the six system layer indexes indicate that every index is independent and their spatial structure is diversiform; there is great difference between different city in system layer index, so the coordination of the urban system layer indexes should be paid attention to and the spatial structure of low carbon competitiveness in Shandong peninsular blue economic zone should be optimized.