To develop a rapid analytical method for the determination of genome size of Atractylodes lancea by flow cytometry (FCM), and to estimate genome size of five typical plant types of cultivated Atractylodes lancea.The fresh young leaves of Atractylodes lancea were used for the preparation of nuclear suspension with two-step protocol. After staining with propidium iodide, the mixture was analyzed by flow cytometry. Zea mays 'CE-777' or Vicafaba 'Inorce' was used for DNA reference standard.The flow cytometric method was developed after screening internal standard, optimizing sample preparation and FCM setups. The narrow leaf type of Atractylodes lancea got the biggest genome size, whereas the smallest one was fasciated stem type. It was suggested that parted leaf might be caused by genome size decrease.The methodology presented in this study is suitable for measuring the genome size of Atractylodes lancea. This study also provides useful information on population variation, evaluation of germplasm resources, and breeding of Atractylodes lancea.