In mountainous area of Oze national park and Chubu Sangaku national park, the spread of alien revegetation grass species were investigated around artificially revegetated slopes in order to understand the characteristics of escape site after revegetation. The roads of approximately 5m width and passed over 10 years after artificial slope revegetation construction were selected in each park. The investigation quadrates were set up on the roadside within the length of 500-1000m and in the adjacent forest. We measured height and coverage rate of each vascular plant species, and height and coverage rate of each stratification of the plant communities. Moreover, we measured relative photon flux density on the ground, inclination and azimuth in the quadrates for understanding environmental condition. Total number of species was 434. Alien revegetation species occurred frequently were Agrostis gigantean Roth., Festuca arundinacea Schreb., Dactylis glomerata Linn., Phleum pratense L., Trifolium repens Linn. These alien revegetation grass species frequently occurred on the roadsides. This study discussed the relations between these species coverage rate and the environmental variable to comprehend escape site characteristics of them.