Abstract: In order to understand the effect of weanling stress on serum lipid metabolism of piglets, 12 weaned piglets with similar body weight were randomly selected, and serum lipid metabolism indexes of their blood were determined when piglets were weaned, 7 days and 14 days after weaning. Result showed that CHO and TG activities of piglet serum were significantly or very significantly increased, but HDL and LDL activities of serum had no significant change. It is suggested that after piglets were weaned for 14 days, they strengthened to absorb lipid materials, and fat deposition increased, so serum nutrients should be properly added into feed during this stage, and it is helpful to adjust body′s metabolism and nutrition regulation.