The invention relates to cohesive glue for a flexible decorative tile and a manufacturing method thereof; the cohesive glue is composed of the following raw materials by weight proportion: 0.3-1.5 percent of water-retaining agents, 28-48 percent of water, 0.3-2 percent of thickeners, 48-68 percent of polymer latex, 0-0.35 percent of ultra-violet absorber, 0-0.42 percent of antioxidant, and 0.7-4.2 percent of film-forming additives; the manufacturing method is that: 1-3 percent of the water-retaining agents, 93-97 percent of water and 1-4 percent of the thickeners are mixed to prepare water-holding thickening liquid for spare, and then 94-98 percent of the polymer latex, 0-0.5 percent of the ultra-violet absorber, 0-0.6 percent of the antioxidant and 1-6 percent of the film-forming additives are mixed to prepare polymer film-formation weather-proofing modified liquid for spare, and 30-50 percent of the water-holding thickening liquid and the polymer film-formation weather-proofing modified liquid are formulated to prepare the cohesive glue for the flexible decorative tile. The cohesive glue has the advantages of no taste, no toxicity, high first sticking intensity, low volume weight and rapid construction speed.