Disclosed are a greenhouse environment regulation method, device and a smart greenhouse. The greenhouse environment regulation method comprises: acquiring air temperature information and relative humidity information of the greenhouse environment (S101); calculating a saturation water vapor pressure difference in the current greenhouse environment by using the air temperature information and the relative humidity information (S102); determining whether the saturation water vapor pressure difference is within a preset suitable range (S103); if so, determining the current greenhouse environment as a suitable environment (S104); and if not, performing a corresponding regulation operation according to the saturation water vapor pressure difference and the preset suitable range (S105). This manner of regulating a greenhouse by calculating the saturation water vapor pressure difference can take two environmental factors including temperature and humidity into account at the same time, thereby being more comprehensi
