Abstract: Natural revegetation on granite highway slopes in the mountainous area of Central Shandong Province was evaluated at quadrat level using a vegetation restoration index (I_VR) just established. Key habitat factors affecting natural vegetation restorability were identified and a model was built up for predicting natural revegetation based on the area index of rock crevice and rock platform () and years of restoration. Results show that habitats different in condition differed rather sharply in natural revegetation on rocky highway slopes, with the highest and lowest quadrat I_VR being 1.89 and 0.29, respectively, and the average vegetation coverage (35.7%) and average aboveground biomass (147.7g•m^-2) of the quadrat group (Group A) which is poor in revegetation being no more than one half and one third, respectively, that of the quadrat group (Group C) which is good in revegetation; Of the seven habitat factors closely related to I_VR, five are morphological factors characterizing development degree of the rock crevice and rock platform and thickness of the soil layer, also their parameters between Group A and Group C varied significantly (P＜0.05), which demonstrates that natural vegetation restoration and restoration ability are well related to habitat morphostructural characteristics of the rsocky highway slopes, and significantly affected by the development level and amount of rock crevice and rock platform; and I_Acp is a critical parameter indicating natural vegetation restorability and one to predict natural revegetation.