Many ecologists are struggling to quantify the species richness in a particular landscape or region. The number of species increases with sample area. Species-area relationship is often used to estimate species richness of a particular region. This study used species-log (area) curves, corrected with Jaccard¡¦s coefficients for within-vegetation type heterogeneity, to estimate species richness and to describe vascular plant species composition in Taiwan Forestry research Institute Tai-Ma-Lee Experimental Forest. In the study area, the author recorded 748 plant species, including 98 endemic species, 21 rare species and 36 naturalized species. There are estimation of 701 species (95¢H CI¡×651~758 species) in the 583-ha natural forest area, 819 species (95¢H CI¡×744~889 species) in the 291-ha plantation area, 560 species (95¢H CI¡×508~641 species) in 8.1-ha forest road. As plantation area is not well-sampled, the total species number in the 947-ha study area could not be estimated. When use 0.1 Modified-Whittaker sampling techniques to assess plant diversity, it is possible to use elevation division, instead of vegetation type, to estimate species richness.