Abstract: In this study, the colitis preventive effects of Lactobacillus plantarum YS-1 (LP-YS1) were studied using an animal experiment.The mice were divided into five groups, which were normal group, model group, LB (Lactobacillus bulgaricus) treated group, low and high concentrations of LP-YS1 (Lactobacillus plantarum YS-1) treated groups, the research object smeard (0.20mL) and clystered (0.15 mL) 1%oxazolone induced colitis in BALB/c mice were detected respectively.The mice DAI value, colon weight/length ratio, serum (IL-2 and IL-10 cytokine levels) and colon tissue index (MPO, NO, MDA, GSH levels and n NOS, e NOS, i NOS, c-Kit, SCF, IL-8, CXCR2 mRNA expression) were used for determination of preventive effects of LP-YS1.The experiment results showed that LP-YS1 significantly reduced (p<0.05) DAI of colitis mice.It could also inhibit the colon length shortening caused by colitis and increase the weight/length ratio of colon.LP-YS1 could significantly reduce the activity of MPO, NO, MDA and increase the activity of GSH in colon tissue of mice with colitis (p<0.05) .LP-YS1 also could significantly increase the serum IL-2 cytokine level and reduce IL-10 level in mice with colitis (p<0.05) .RT-PCR results also showed that LP-YS1 could significantly increase (p<0.05) n NOS, e NOS, c-Kit, SCF expression and decrease i NOS, IL-8, CXCR2 expression in colon tissue of mice.Thus, it can be seen that LP-YS1 has a good preventive effect on oxazolone induced experimental colitis.