Abstract: The experiment was conducted to study the effect of L-arginine on the content of protein，DNA, RNA and disaccharidase activities in small intestinal mucosa and the content of D-xylose in plasma of weanling piglets after lipopolysaccharide (LPS) challenge.Pigs were allotted into four treatments (6 replicates/treatment and 1 pig/replicate) including: (1) Nonchallenged control (NONC); (2) Challenged control (CHAC); (3) 0.5% arginine (0.5% Arg); (4) 1.0% arginine (1.0% Arg). On d 16 after weanling, pigs in the CHAC, 0.5% and 1.0% Arg groups were injected intraperitoneally with 100 μg/kg BW LPS, whereas pigs in the NONC group were injected with an equivalent amount of sterile saline. D-xylose was orally administrated 2 h at the dose of 1 mL/kg BW after LPS challenge, and blood samples were collected 3 h after LPS challenge. On 48 h after LPS challenge, the pigs were slaughtered to collect intestinal mucosa for analysis. The results showed that: (1) Compared with NONC, the protein content of duodenal mucosa, DNA content of jejunal and ileal mucosa, suctase activities of jejunal mucosa, lactase, suctase, maltase activities of ileal mucosa and D-xylose content of plasma for CHAC were decreased significantly (P<0.05), which indicates that LPS induces intestinal damages. (2) Compared with CHAC, the protein content of duodenal mucosa, DNA content of jejunal mucosa, lactase, suctase, maltase activities of ileal mucosa, D-xylose content of plasma for 0.5% Arg group, and DNA content of jejunal mucosa, suctase activities of jejunal mucosa, lactase, suctase, maltase activities of ileal mucosa, D-xylose content of plasma for 1.0% Arg group were numerically higher, and had no significant difference from those of NONC (P>0.05), which indicates that L-arginine can alleviate the intestinal damage induced by LPS to some degree.