An assessment of alien plant invasive and is very important to control the them at protected areas of tropical forest. Sixty-four alien invasive plant species belong to twenty-three families were recorded at six conservation areas of West Sumatra. The species composition of invasive plant were different among those six conservation areas. Kebun Raya Solok had the highest number of species and genera (41 and 39, respectively) and G. Talamau had the lowest one, with ten species and ten genera. Increasing the number of species and genus of invasive plant concordance to disturbance of the studied areas. More than 50% of invasive plant species in School forest for biological research and education, Limau Manis, were similar to those invasive plant species in Kebun Raya Solok, West Sumatra. In contrast, only 13% of invasive plant species from Kebun Raya Solok were similar to G. Talamau. It is very important to note that three invasive tree species (Acacia auriculiformis, Acacia mangium & Arenga obtusifolia) were detected in three conservation areas and the latest one was dominantly distributed in Lembah Anai and Rimbo Panti Natural Reserve. The existance of these invasive species: Imperata cylindrica, Clydemia hirta, Lantana camara, Leucaena leucocephala, Mikania micrantha and Mimosa pigra into conservation areas in West Sumatra have to be warned cause of the severe effect to the biodiversity. The invasive species from family Asteraceae (except Ageratum conyzoides), Leguminosae and Graminae tend to had the xenogamy breeding system that implied the high level of genetic diversity and well adapted various habitats.
