Based on the model of multispecies competitive coexistence, two assumptions of the competitive coexistence patterns between the exotic species and the local species are proposed in this paper. One pattern is the queue-jumping competitive coexistence, and another pattern is the equal niche competitive coexistence. Which competitive coexistence pattern that the exotic species will take depends on the proportional abundances of the exotic species under the two kinds of patterns. Following the two assumptions, the corresponding modes are established. Then we employ Mathematica 4.0 to simulate the dynamics of multispecies competitive coexistence. We find: under the queue-jumping competitive coexistence pattern, if the differences in the competitive ability among the local species were significant, the invasion of the exotic species would be inclined to damage the local rare species; if the differences were extremely small, all the local species are inclined to be immune to the invasion. We also find: under the equal niche competitive coexistence pattern, apart from the local species whose niche is the same as the exotic species′, the remaining local species are completely immune to the invasion. The extent of the effect of the invasion on the local species under the latter pattern, is subject to the preliminary proportions of the exotic species and the local species affected.