Abstract: Inorder to reduce individual deviation, twelve piglets from 2 farrows were randomly dividedinto 2 groups, 6 piglets each, designated as treatment group and control group, BCG orequal volume of saline solution was administered intramscularly into the piglets when 40days old, The assay result showed that the proliferation response of peripheral bloodT-cell and the bacteriocidal capability of piglets peaked at 7 and 3 days postimmunization, and then began to decrease from day 10 and 7, while there was no significanteffect on the total number of white blood cell and active T-lymphocyte. In conclusion, BCGcould significantly enhance cellular immunity and disease-resistance capability of theweaned piglets.