This paper constructs an evaluation index system of science and technology innovation efficiency, uses the DEA-BCC model to analyze the level of science and technology innovation efficiency of 11 coastal provinces (municipalities) in China in 2021 statically, analyzes the reasons for the non-DEA-effective provinces (municipalities), and uses the Malmquist index. Dynamic analysis of the spatio-temporal changes of science and technology innovation efficiency in 11 coastal provinces (municipalities) of China from 2011 to 2021. The findings are as follows: From the static analysis, the overall efficiency of science and technology innovation in China's coastal provinces (cities) in 2021 is relatively high, with the highest level of science and technology innovation efficiency in the eastern Marine economic circle and the weakest one in the southern Marine economic circle; Pure scale efficiency is an important factor affecting whether coastal provinces (cities) are in the effective state of DEA. From the dynamic analysis, the overall state of science and technology innovation in China's coastal provinces (cities) was on the rise during the evaluation period, and the M-index showed a "declining - rising - declining - rising" cycle. The three major Marine economic circles are 1.064, 1.037 and 1.032 from north to south, showing a spatial layout of "high in the north and low in the south". Comprehensive technical efficiency and pure technical efficiency are the key factors determining the spatial layout of scientific and technological innovation efficiency. Based on this, suggestions are put forward to adhere to the market demand orientation, strengthen the dominant position of enterprises in science and technology innovation, optimize the investment of scientific research resources, enhance the vitality of science and technology market, break regional restrictions, and realize the coordinated development of coastal science and technology innovation.