Urban-rural green development efficiency is of great significance to the construction of efficient and low consumption green development model, the sustainable development of social economy and the realization of urban-rural integration. Based on 13-year panel data of 35 counties in Lunan Economic Belt (also known as Southern Shandong Economic Belt), the article estimated the spatio-temporal differentiation characteristics and driving factors of urban-rural green development efficiency in the study area by using DEA-Malmquist index method, decoupling state model of urban-rural green development efficiency, geographic detector and other econometric models. Research shows that: (1) Technological progress is the main source of green TFP growth, but its contribution is declining, while the pure technical efficiency and scale efficiency to green TFP growth is increasing year by year. (2) The growth of green TFP has spatial differentiation, and the high and sub-high efficiency areas of green TFP are different during the research period. The growth tends to concentrate in the northeast and southwest of Shandong province. (3) The decoupling relationship between urban and rural green development efficiency in the study area appears repeatedly, from negative decoupling (coupling) to decoupling and then to negative decoupling. On the whole, the green development of urban and rural areas is in the stage of dynamic change and non-coordination (or low-level coupling). (4) The number of students in ordinary middle schools, grain production and savings deposit balance of urban-rural residents are the driving indexes of urban-rural green development efficiency. The explanatory power of factor interaction on the urban and rural green development efficiency is far greater than that of single factor, reflecting the complexity of the driving factors of urban-rural green development efficiency in the Lunan Economic Belt.