Paeonia ostii is one of the important woody oleaginous plants, and is cultivated on a large scale in China. The main purpose of this study is to evaluate the characteristic difference of P. ostii seed and oil sourced different geographical regions in China. The thousand seed weight (TSW), oil content and kernel content of the P. ostii seed, the composition and content of the main fatty acids, and the physicochemical characteristics of the seed oil of 62 P. ostii seed samples from different cultivation regions were monitored and evaluated in this study. The results showed that there were extremely significant difference among the TSW and the contents of the main fatty acids in P. ostii seed and oil. The geographical regions were related to the variability in TSW, the contents of the main fatty acids (FAs) and the total content of the main fatty acids (TCMFA), perhaps due to the influence of environmental factors, and the water, fertilizer application, crop management, or other factors. P. ostii would become a kind of woody oleaginous plant and an industrial crop with broad prospects for its high content of alpha-linolenic acid (ALA) and the high oil content of the seeds.