The protective effect of Lactobacillus plantarum YS3 (LP-YS3) on ulcerative colitis (UC) was assessed using a mouse model of dextran sodium sulfate (DSS)-induced colitis. Different concentrations of LP-YS4 were administered to the experimental mice by daily gavage. Several inflammatory and biochemical indices, such as interleukin-2 (IL-2), interleukin-10 (IL-10), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), glutathione (GSH), malondialdehyde (MDA), myeloperoxidase (MPO), and nitric oxide (NO), were examined in mouse serum and colon tissue. The mRNA and protein expression levels of c-Kit, CXC chemokine receptor type 2 (CXCR2), interleukin-8 (IL-8), and stem cell factor (SCF) in mouse colon tissue were assessed using Western blot and quantitative polymerase chain reaction (qPCR) assays. The findings indicated that LP-YS3 remarkably decreased the disease activity index (DAI) of UC mice (p < .05), inhibited colon length shortening induced by UC, and elevated the value of colon weight/length ratio. LP-YS3 could also markedly reduce (p < .05) the activities of MDA, MPO, and NO; while an increase in the GSH content in the colonic tissue of UC mice. Moreover, LP-YS3 remarkably increased (p < .05) the serum level of IL-2 in UC mice, while reduced those of IL-10, IL-6, IL-1β, TNF-α cytokines. qPCR data revealed that LP-YS3 could markedly upregulate the expression levels of c-Kit and SCF, while downregulate those of CXCR2 and IL-8 in the colonic tissue of UC mice (p < .05). LP-YS3 exerted an outstanding protective effect on DSS-induced colitis in C57BL/6J mice, especially at higher concentrations. PRACTICAL APPLICATIONS: Lactobacillus plantarum YS3 is a newly isolated and identified lactic acid bacteria. This study confirmed that L. plantarum YS3 can inhibit colitis and has good probiotic potential, which needs further development and utilization.