The disturbance of intestinal microorganisms and the exacerbation of type 2 diabetes (T2D) are mutually influenced. In this study, the effect of exopolysaccharides (EPS) from Lactobacillus plantarum JY039 on the adhesion of Lactobacillus paracasei JY062 was investigated, as well as their preventive efficacy against T2D. The results showed that the EPS isolated from L. plantarum JY039 effectively improved the adhesion rate of L. paracasei JY062 to Caco-2 cells (1.8 times) and promoted the proliferation of L. paracasei JY062. In the mice experiment, EPS, L. paracasei JY062 and their complex altered the structure of the intestinal microbiota, which elevated the proportion of Bifidobacterium, Faecalibaculum, while inversely decreasing the proportion of Firmicutes, Muribaculaceae, Lachnospiraceae and other bacteria involved in energy metabolism (p < 0.01; p < 0.05); enhanced the intestinal barrier function; promoted secretion of the gut hormone peptide YY (PYY) and glucagon-like peptide-1 (GLP-1); and reduced inflammation by balancing pro-inflammatory factors IL-6, TNF-α and anti-inflammatory factor IL-10 (p < 0.01; p < 0.05). These results illustrate that EPS and L. paracasei JY062 have the synbiotic potential to prevent and alleviate T2D.