Bai ji (Rhizoma Bletillae) is a well known traditional Chinese medicine, and Taiwan bai ji (Bletilla formosana (Hayaata) Schltr.) is commonly available in Taiwan. In this study, B. formosana (Hayata) Schltr. was collected from Wutai township (Pingtung county), Shaolin township (Hualien county) and Datung township (Yilan county), while B. formosana (Hayata) Schltr. f. kotoensis (Hayata) T. P. Lin was collected from Orchid Island (Taitung county). Four components, namely militarine, cinnamic acid, 1,8-bi(4-hydroxybenzyl)-4-methoxyphenanthrene-2,7-diol (BHMD), and 4,7-dihydroxy-1-p-hydroxybenzyl-2-methoxy-9,10-dihydro-phenanthrene (DHMD), were used as marker compounds for quantitative analysis by HPLC. The Folin-Ciocalteu method was used to measure the total phenolic content in extracts. DPPH radical-scavenging assay was employed to measure antioxidant activity. Our results showed that the contents of cinnamic acid and militarine in the tubers from Yilan were higher than those in other regions. Moreover, the contents of BHMD and DHMD in the tuber of the plants from Orchid Island were higher than those in other regions. In addition, the content of the components in the seedlings grown by tissue culture were lower. B. formosana (Hayata) Schltr. f.kotoensis (Hayata) T. P. Lin from Taitung had a higher total phenolic content and higher DPPH scavenging ability.