Meteorological and citrus data are obtained from the two basicpoints (Dongshan, Wuxian county, Jiangsu province and Xinhuacounty, Hunan province) and the area consisting of 18 counties in China’s eastern subtropics, and the relationship between the formation of citrus quality and meteorological conditions are examined in bothtime and spatial sequencies. Studies are made on the trend relation be-tween the variations of meteorological factors and citrus quality at thetwo points and on the effects of meteorological conditions of differentlatitudes, elevations, topographies and locations on citrus quality in the18-county area. It is found by curve function simulation that the dire-ctivity function curves fit well with actual processes in the formationof citrus quality. The purpose of this paper is to provide scientificgrounds for the development of citrus production and the exploitationof the climatic resources in China’s eastern subtropics.