【Abstract】 Objective To study the antifatigue effect and mechanism of Brassica rapa L extract of highaltitude crops. Methods Male ICR mice were used as experimental animals, and the mice were randomly divided into three groups. Brassica rapa L extract was given to the mice by continuous gavage for 14 days, rhodiola group mice and the control group mice were intragastrically administrated by rhodiola oral liquid andsterilized deionized water in the same manner. The fatigue swimming time of the mice was respectively measured on the 7th and 14th day of the gavage, then testing the blood glucose levels, serum lactate levels and serum lactate dehydrogenase levels. Extracting the mice small intestine tissue，and sent to bio company for sequencing. The sequencing results were analyzed for differential expression. At the same time, lactate dehydrogenase A, the major subunit of lactate dehydrogenase (LDH), were predicted by correlation analysis prediction software. Results In the entire experiment, the blood glucose level of the Brassica rapa L group and rhodiola group did not change significantly (P＞0.05). Compared with the control group, the antifatigue swimming time of the mice in the Brassica rapa L group was prolonged with the prolongation of time, and it significantly prolonged at 14th days (P＜0.01). The serum lactic acid content significantly decreased on the 7th day (P＜0.01), in the meantime, serum lactate dehydrogenase activity also increased significantly on the 7th day (P＜0.01); However, compared with the Rhodiola group mice, there was no significant difference. The Rhodiola group mice also showed a significant increase in antifaigue swimming time (P＜0.01) and a significant decrease in serum lactic acid content at 14th days(P＜0.01), and significantly increased serum lactate dehydrogenase activity (P＜0.05). After analyzing transcriptome sequencing results, predicted five interacting genes of lactate dehydrogenase A(LDHA). It is estimated that the Brassica rapa L extract may be regulated by HIF1A and ABCC9 for the activity of lactic acid dehydrogenase by consulting the literature analysis. Conclusion Brassica rapa L extract has the effect of increasing serum lactate dehydrogenase activity and reducing serum lactic acid content of mice, but has no effect on blood glucose levels in mice. The effect of Brassica rapa L on the expression and activity of lactate dehydrogenase may be achieved by HIFA and ABCC9 separately; Longterm use of Brassica rapa L extract can accelerate clearance of serum lactic acid by increasing serum lactate dehydrogenase activity, consequently achieving similar antifatigue effects to Rhodiola.