The invention discloses an over-wall high-elasticity joint material for steel bridge deck pavement maintenance and a preparation method and a use method of the over-wall high-elasticity joint material. The over-wall high-elasticity joint material consists of a main agent A and a curing agent B, wherein the main agent A comprises the following components in parts by weight: 50-150 parts of molten polysulfide rubber, 20-100 parts of a plasticizer, 0-30 parts of a tackifying resin, 50-250 parts of packing and 1-3 parts of a coupling agent; the curing agent B comprises the following components in parts by weight: 30-60 parts of a vulcanizing agent, 30-60 parts of a plasticizer, 10-30 parts of packing and 1-5 parts of a promoter; the weight ratio of the main agent A to the curing agent B is 100:(5-15). According to the product disclosed by the invention, the packing with thixotropism is introduced into the joint material on the basis of a rheology principle, so that the flowability of the high-elasticity joint material on an original pavement cross section is degraded, and sealing and adhesion of new and old pavements are achieved. In addition, the product is based on molecule chain segment movement and mutual action mechanisms, and the movement resistance of molecule chains of high-flexibility polysulfide rubber is further weakened by using the plasticizer, so that the elasticity of the over-wall high-elasticity joint material is greatly improved, and synergic deformation of the new and old pavements is achieved.