In order to define the adaptability to different light intensities in genus Alcantarea, mature plants of 3 giant species of Alcantarea were treated under full sun light (CK), 40% light (S₄₀) and 10% light (S₁₀) for 4 nearly months. The variation on leaf anatomy structure and the amounts of photosynthetic pigments in the leaf of different treatments were measured and detected. The results show that： (1) the features of leaf anatomic structure of 3 Alcantarea species are similar, with single layer of small epidermal thickwalled cells on both surfaces, and the epicuticular stratum is welldeveloped. A multicellular aquiferous hypodermis is formed beneath the epidermal cells, palisade parenchyma (PP) and spongy parenchyma (SP) are well differentiated in mesophyll, and the PP is arranged in arches, an aeration channel with cross sections shaped in ellipse or oblong formed under the PP and filled with SP. These air channels are connected to the substomatic chambers on the abaxial surface, which contribute to the gas exchange in the mesophyll, ensuring that there is sufficient gas for photosynthesis although the leaf base sits in water year around. (2) The effects of environmental light intensity on leaf anatomical structure of Alcantarea varied with species, A. glaziouana is more sensitive to the changes of light intensity, with significant differences on the leaf thickness, cuticle thickness, the proportion of spongy parenchyma and the ratio of palisade and spongy under different light intensity, as for A. imperialis and A. ‘Grace’, except for the cuticle thickness, the other characteristics did not change significantly. The stomatal density on the leaf of 3 Alcantarea species has almost no change under different light treatments, and the stomatal density of A. imperialis and A. ‘Grace’ was similar and significantly higher than that of A. glaziouana, indicating the difference of anatomical features among species was determined genetically, and relatively stable. (3) Light intensity had the significant effect on the photosynthetic pigments of 3 Alcantarea species, and different species responsed to the light variation differently. The value of Chla/Chlb of 3 Alcantarea species under full light (CK) and 40% light (S₄₀) ranged from 2.73 to 3.03, which was close to the characteristics of leaves grow under sunny place, while all decreased under 10% light (S₁₀), and A. glaziouana with the lowest Chla / Chlb as to 2.53, close to the value of leaves grow in shade. The results showed that the tolerance to strong light was A. imperialis ［red leaf form］>A. ‘Grace’> A. glaziouana, while to the weak light environment, the 3 species behaved the opposite. A. imperialis［red leaf form］ and A. ‘Grace’ are suitable for outdoor with bright light or in semishade; while A. glaziouana is suitable for outdoor shade, and avoiding direct sunlight in hot summer. It also suitable to the exhibition greenhouse which is featured with weak light environment.