The genus Cryptocarya within the Lauraceae family is widely distributed throughout the tropic forests including the Southeast Asian region. The total number of Cryptocarya is estimated between 200 and 250. However Cryptocarya has not been fully studied and still remains difficult to identify. Thus we are carrying on a series field survey of plant biodiversity in Southeast Asia, including Cambodia, Indonesia, Laos, Malaysia, Myanmar, Thailand, and Vietnam. We used both plots survey and general specimen collecting methods at different elevations of the tropical mountains. In addition, we applied the both morphology observation and phylogenetic analysis based on DNA barcode ITS to identify the Cryptocarya. As a result, within 83 collecting Cryptocarya samples, 20 Cryptocarya species were identified and 9 species are not identified including 3 new candidate species, which are Cryptocarya bokorensis sp. nov., Cryptocarya kaengkrachanensis sp. nov., and Cryptocarya honbaensis sp. nov..