Road is a corridor built by people to promote cultural and material exchanges， and plays an important role in the foundation of social， economic and cultural development. Because of the big difference in habitat between road corridor and forest interior， plants are not easy to grow. How to construct roadside vegetation through ecological restoration has become one of the focus issues of road corridor ecological construction. In this study， a total of 144 roadside plots were set up in 18 suburban roads in Guangzhou after a long period of recovery， in which plant communities were investigated， and then the data were comprehensively analyzed. We also compared the environmental factors of 6 rods with their adjacent forest interior habitats， and determined the physiological and ecological indexes of representative dominant suitable species. We try to answer 3 scientific questions： （1） What are the environmental factors restricting plant growth along the road compared with forest interior？ （2） What are the natural plants in the roadside？ （3） Why do these plants grow in roadside environment？ The main results are as follows： （1） Compared with forest interior， the main ecological factors limiting the growth of plants in roadside habitats are intense light， high temperature and drought. （2） A total of 33 natural dominant species were selected， of which 16 were widely distributed along roads and in forest interior， and 17 were mainly widely distributed in the roadside. There were 2 evergreen species and 9 deciduous species； the deciduous species accounted for 27.3%. There were 24 tree species， 6 shrub species and 3 vine species， accounting for 72.7% of the total. （3） The natural plants along the road had the characteristics of increasing number and quantity of positive tree species， dwarfing of tree form， high sharpness， thickening of total leaf thickness， palisade tissue and spongy tissue， etc. It has the physiological and ecological characteristics of higher net photosynthetic rate and water use efficiency； These characteristics also explain the mechanism of its adaptation， and can be used as the scientific basis for selecting species of roadside restoration. This study reveals the mechanism of why these plants can naturally adapt to the roadside habitat in suburban Guangzhou， and enriches the ecological construction theory of highway ecological corridor. The proposed biogenic dominant species is the priority species selection for rapid ecological restoration of highway corridor vegetation in suburban Guangzhou， and has a reference value for road ecological corridor construction in other areas.