【Objective】 The purposes of the study was to elucidate the adaptive traits of vegetative organ structure in Orchidaceae to Karst habitats, reveal the survival strategies of different orchid species in response to habitat heterogeneity, and provide theoretical support and reference for the research, protection and development of orchid species. 【Methods】 An investigation was conducted on the leaves, pseudobulbs, and roots of six Orchidaceae species with varying life forms in the Karst region of Beipan River, Guizhou Province. The paraffin section technique was employed to examine the structure and quantify relevant parameters. Descriptive and variance analyses, correlation analysis, and principal component analysis were employed for data analysis. 【Results】 The findings revealed that: (1) There were significant differences in structural characteristics among different orchid species. Cymbidium qiubeiense, Cymbidium cyperifolium, Cymbidium lancifolium and Pholidota leveilleana were isofacial leaves with thin leaves. The leaves of Coelogyne flaccida and Bulbophyllum andersonii were heterofacial, with palisade tissue and spongy tissue differentiation, and the leaves were thicker. (2) Pseudobulbs are mainly composed of epidermis, basic tissue and vascular bundle. The cells of basic tissue are small and the density of vascular bundle is large. The basic tissue cells of the pseudobulbs of epiphytic orchid are larger and the water storage structure is more developed. (3) The root coat and cortex of ground orchid are thick, the root coat cells are closely arranged, and the cortical cells are more small layers. The rhizome and cortex of epiphyte orchids are thin, and the cortical cells are large. (4) The thickness of the lower epidermis of leaves was significantly positively correlated with leaf thickness, leaf vascular bundle diameter, leaf flesh thickness, and leaf vein thickness (P < 0.01), while leaf flesh thickness was significantly negatively correlated with lower cuticle thickness and stem vascular bundle diameter (P < 0.05). Stem diameter was significantly positively correlated with epidermis thickness, stem vascular bundle number, and stem cross-sectional area, while stem vascular bundle diameter ratio was significantly negatively correlated with stem diameter, epidermis thickness, stem vascular bundle number, and stem cross-sectional area. The various indicators of roots were significantly positively correlated, and root diameter, root sheath thickness, and cortex thickness were significantly negatively correlated with root vascular bundle diameter ratio. 【Conclusion】 The research revealed that orchids possess a notably resilient convergent adaptability in comparable habitats, as evidenced by their stable root structure. Furthermore, the leaf and pseudobulb structures of orchids mutually facilitate and synchronize with one another, constituting the primary mechanism by which orchids respond to the arid karst environment.