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With SPOT—NDVI data and land use classification data, a remote sensing inversion was performed on multiple cropping index (MCI) in 2000, 2005 and 2010 in the Bohai Rim in China and the factors influencing multiple—cropping index change were explored quantitatively with a geographical detector methods model.The results showed that the multiple—cropping index from south to north reduced from 285% in plains to 75% in mountains, showing latitudinal zonality, and the multiple—cropping index was lower (35%-55%) in hills, plateaus and mountains than in plains at the same latitude, showing vertical zonality, because of the different hydrothermal conditions.During 2000-2005, the multiple—cropping index rose in plain areas, but declined in plateaus, mountains and hills.During 2005-2010, in contrast, the declined MCI started increasing, and the index in plains kept stable.It is concluded that the grain yield per unit area is a dominant factor influencing multiple—cropping index change, followed by cultivated land area per capita, labor force transfer rate and number in rural areas, agricultural production condition, agricultural modernization level, as well as geographical location.With rural—urban transition development, the subjects engaging in agricultural production are weakening.In plain regions, it is necessary to promote rural land circulation in a rational and well—organized way to develop new—type agricultural cooperative association and facilitate agricultural modernization.On the other hand, it is of significance to organize comprehensive consolidation and improvement including land, water, road, forest and villages, to strengthen high—standard farmland construction and guarantee regional grain safety and urban—rural transition development.In hills and plains, it is recommended to develop characteristic agriculture according to local conditions, adjust agricultural structure properly, and strengthen competitiveness of characteristic industries, so as to improye economic benefits from agricultural lands, increase farmers' income, and avoid extension of abandoned lands, with highly—efficient and intensive utilization of agricultural lands.