Honesty （Lunaria annua L.） belongs to the Brassicaceae family and is a biennial herb with high nutritional and medicinal value， as it contains nervonic acid， and its seeds are rich in oil. In order to explore the types and contents of fatty acids during the development process of the fruit， as well as the synthesis characteristics of very-long-chain fatty acids， especially nervonic acids， this study used gas chromatography and mass spectrometry to analyze the fatty acid components and content of nervonic acids in Lunaria， Arabidopsis， Borage， and Malania fruit. The results showed that a total of 10 types of fatty acids were involved in fatty acid metabolism during the development process of the Lunaria fruit， seven detected in seeds and eight in pericarps. Most of them are long chain and very-long-chain unsaturated fatty acids. The fatty acids in seeds were mainly composed of palmitic acid， stearic acid， oleic acid， linoleic acid， linolenic acid， erucic acid and nervonic acid. The content of palmitic acid， stearic acid， linoleic acid and linolenic acid gradually decreased along with seed development. The oleic acid， erucic acid and nervonic acid gradually increased along with seed development and accumulated in large quantities in the first 25-35 days after anthesis. The pericarp was free of erucic acid and nervonic acid， but specializes in behenic acid， lignoceric acid and cerotic acid. Lunaria， Borage and Malania seeds all contain erucic acid and nervonic acid. Woody plant Malania seed has the highest content， followed by Lunaria， and Borage that has the lowest content. The content of nervonic acid in seeds of the three plants is significantly positively correlated with the content of erucic acid. This study elucidated the characteristics of fatty acid metabolism and accumulation of nervonic acid during the fruit development process of Lunaria， providing new ideas for fully utilizing the germplasm resources of Lunaria and expanding the pathways for obtaining nervonic acids.