Astragalus membranaceus (AM) and Panax ginseng (PG) are two herbal products with a long history of clinical usage in traditional Chinese medicine (TCM), used in treating a variety of diseases especially in stimulating or inhibiting the immune system. To elucidate the immunity effect of these two traditional Chinese medicine on animal model, four pharmacodynamic indexes (spleen index, thymus index, splenic lymphocyte proliferation and cytotoxic activity of natural killer (NK) cells) were observed on mice. Furthermore, metabolic profiles of plasma were also analyzed by ultra-performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UPLC-Q/TOF-MS, LC-MS) method. All mice were intragastric administrated at three doses (low dose, moderate dose and high dose) once daily for 30 days. Principal components analysis (PCA) and orthogonal projection to latent structure discriminant analysis (OPLS-DA) were performed on LC-MS spectra of plasma, showing that all administration groups developed the disturbance of internal milieu, compared to the blank control (BC) group. Besides, correlation analysis was conducted between pharmacodynamic index and metabolic index. It indicated that uracil, lysoPC(18:3(6Z,9Z,12Z)), sphinganine, LPA(0:0/16:0), UDP-glucuronate, PC(14:0/18:0) were five main endogenous substances, much closely related to four immunological indexes. Glycerophospholipid metabolism was found in both AM and PG groups. Pyrimidine metabolism and sphingolipid metabolism were closely regulated in AM groups. Energy metabolism (starch and sucrose metabolism, Pentose and glucuronate interconversions, together with glycerolipid metabolism) and glycerolipid metabolism were found in PG groups. These findings could contribute to the understanding of mice plasmatic metabolic profiling after long-term administration. Comparative immune-related metabolomic analysis of AM and PG was obtained on the base of pathway analysis of immune-related biomarkers. PG groups trended to have effect on cytotoxic activity of NK cells. AM groups trended to effect thymus index. Our work provides a detailed interpretation of immunological characteristics in different traditional Chinese medicine on metabonomic level.