To investigate the effects of negative therapy at back meridian points on blood gas components and immune functions in male college students, this study was conducted on treatment types(abdomen group and back group) at three sampling times (before, post-2 wks and post-4 wks) by using $2{\times}3$ factoral design. Blood gas $components(pH,\;PCO_2,\;PO_2,\;HCO_3^-,\;O_2SAT,\;BE)$, red blood cell, hematocrit, hemoglobin, white blood cell and subsets(neutrophil, basophil, eosinophil. lymphocyte, monocyte), total T cells, helper T cells, suppressor T cells, Th/Ts ratio, total B cells, serum immunoglobulin levels (IgG, IgA, IgM, IgD, IgE), Cytokines(Interlukin$-1{\beta}$, -2, -4, 2 receptor, -6 and ${\gamma}$-interferon), NK cells were measured. Collected with data were analyzed statistically by repealed measured ANOVA. The pattern of change between two groups for hematocrit, hemoglobin, suppressor T cells, interleukin-6, ${\gamma}-interferon$, NK cells at post-2 weeks and BE, lymphocyte, basophil at post-4 weeks was significantly different(p<0.05) And also the pattern of change over time for ${HCO_3}^-$(2 wks vs 4 wks), WBC, neutrophil, lymphocyte(0 wks vs 2 wks and 2 wks vs 4 wks) was significantly different(p<0.05). In summary, these data suggest that negative therapy at back meridian points had an effect on blood gas components and immune functions in male college students because practicing negative therapy at back meridian points was not associated with changes of all blood gas components and immune factors but associated with changes of BE, hematocrit, hemoglobin, WBC. neutrophil, lymphocyte, interleukin-6. ${\gamma}-interferon$, NK cells.