With the new development concept of “innovation, coordination, greenness, openness and sharing”, it is of great significance to analyze the green development level of the Yangtze River Delta urban agglomeration to promote regional green transformation. This paper sorts out the green development theory and defines the concept and connotation of the green development level of the Yangtze River Delta urban agglomeration. Based on the PSR theoretical model, a cyclic complex correlation coefficient method is used to screen and build an evaluation system for the green development level of the Yangtze River Delta urban agglomeration, which includes 25 indicators in three levels of urban growth greenness, green wealth, and green policy support. And the green development level of the Yangtze River Delta urban agglomeration is evaluated. The results show that the overall level of green development in the Yangtze River Delta urban agglomeration increased from 2012 to 2017, the spatial distribution of green development levels was uneven, and the level of green wealth pends to be improved. From the three aspects of accelerating the transformation of the industrial structure, giving full play to the location advantage, and improving the performance evaluation indicators, this paper proposes the countermeasures and suggestions to improve the green development level of the Yangtze River Delta urban agglomeration.