The fall armyworm (FAW), Spodoptera frugiperda J.E. Smith is a noctuid moth endemic throughout the Western Hemisphere that has recently become widespread in sub-Saharan Africa. In Asia, FAW was firstly reported at corn fields in India, SriLanka, Bangladeshi, Miyanmar and Thailand in 2018. In January 2019, FAW was also found in Yunnan province of China. In March 2019, the larvae which could be tentatively identified as FAW were caught at a corn field of Plant Protection Center of Lao PDR, which is located in Vientiane, Laos. Species identification was confirmed by DNA barcoding using the COⅠ segment of the four larvae, which were found to be the haplotype of rice strain (COⅠ-RS). The host strain identity was additionally analysed as a Tpi-C (C-strain allele) by Triosephosphate isomerase gene (Tpi) segment located on the Z sex chromosome. The result shows that the FAW specimens in Lao is the subpopulation of COⅠ-RS/Tpi-C (COⅠ and Tpi haplotype combination). It was reported that COⅠ-CS/Tpi-C were more frequently observed than COⅠ-RS/Tpi-C in Western Hemisphere and Western Africa, but COⅠ-RS/Tpi-C were more frequently observed in Eastern Africa. It can be supposed that the subpopulation of COⅠ-RS/Tpi-C in Lao is one of the subpopulations which have migrated into the Indochinese peninsula from Eastern Africa, with more detailed analysis for more diverse nationwide specimens left.