In order to improve the bioavailability of Amaranthus caudalis,the seeds were extracted by Soxhlet extraction with petroleum ether.After the methyl esterification of extract,the fatty acid components of A. caudalis were analyzed and identified by GC-MS,and the biological activities were evaluated by detecting free radical scavenging and bacteriostatic ability.The anti-bacterial activities of the obtained oil were evaluated against two bacterial.Results showed that the oil extraction yield was 2.55%,and mainly composed of palmitic acid (14.09%),linoleic acid (61.35%) and oleic acid (21.39%).In addition,the extract showed relatively high antioxidant property;Moreover,antibacterial assay revealed that the extract exhibited a considerable anti-microbial activity against tested strains.The seed of A. caudalis was rich in fatty acids and exhibited certain antioxidant activity,which has potential development and utilization in future medicine,cosmetic and food industry.