This study was conducted to investigate the effects of adjacent stand on the invasion of Robinia pseudoacacia plantations. The results were as follows. 1) Robinia pseudoacacia tended to invade into all directions regardless of the kinds of adjacent stands. But it was estimated that the invasion of Robinia pseudoacacia into adjacent stands could be very difficult, if the layer structure of adjacent stands were well developed. Whereas, it was estimated that Robinia pseudoacacia more rapidly intruded into adjacent stands, if adjacent stands were opened and bared. 2) Robinia pseudoacacia tended to invade into all aspects regardless of the kinds of vegetation units in the adjacent stands. But the dominance class of Robinia pseudoacacia in the adjacent stands showed a little differences among the vegetation units. The dominance class of Robinia pseudoacacia in Quercus aliena community and Quercus serrata community showed low level as +∼2, while the dominance class of Pinus densiflora community, Pinus rigida community, Quercus variabilis community and Quercus acutissima community represented high level as 1∼4. Also the dominance class of Isodon inflexus subgroup among three subgroups of Pinus densiflora community showed the lowest level as + ∼2.