The invention relates to the technical field of plant cultivation and particularly relates to an ex-situ transplanting cultivation method of wild rhododendron micranthum. The ex-situ transplanting cultivation method comprises the following cultivation steps of digging: when in digging, firstly checking the base part of the trunk of the wild rhododendron micranthum, determining the trend of the root system, starting digging at the position 50cm away from the center of the root system, and noting that the complete root system is retained in digging; pretreatment: cleaning the surface of the rootsystem of the dug plant, and disinfecting; cultivation: putting the treated plant into a container; root irrigation with rooting powder: using a rooting powder solution to irrigate the root of the cultivated plant; curing: watering once every 5-7 days, and controlling the environment conditions that the daytime temperature is 15-25 DEG C, the night temperature is not less than 0 DEG C, the relative humidity is 40% or above and the illumination is 2000-3000Lux. The ex-situ transplanting cultivation method is simple, is convenient in use, and creates a suitable growth environment for the wild rhododendron micranthum by utilizing modern technical means of gardening cultivation so as to effectively protect germplasm resources with development values and lay foundation for population remediation and ecological construction.