The invention relates to a high-elasticity waterborne polyurethane-acrylate composite resin which is prepared mainly from the following raw materials: 7 to 20 parts by mass of aliphatic polyisocyanates with highly symmetrical structure, 25 to 45 parts by mass of polyether polyol, 0 to 0.03 parts by mass of polyurethane catalyst, 0 to 2 parts by mass of low molecular weight alcohol chain extender, 1 to 6 parts by mass of hydrophilic chain extender, 0.4 to 1.5 parts by mass of low molecular weight amine chain extender, 1 to 4 parts by mass of organic amine neutralizer, 20 to 60 parts by mass of (methyl) acrylate monomer and 0.08 to 1.3 parts by mass of free radical initiator. The high-elasticity waterborne polyurethane-acrylate composite resin disclosed by the invention has good mechanical property at different using temperatures. A coating prepared from the high-elasticity waterborne polyurethane-acrylate composite resin not only has excellent mechanical property, but also has excellent water resistance, alkali resistance, stain resistance and ageing resistance, so the high-elasticity waterborne polyurethane-acrylate composite resin is very suitable for preparing the single-component elastic coating in the field of buildings.