The invention discloses a flexible seamless expansion joint connecting material and a preparation method thereof. The flexible seamless expansion joint connecting material is prepared from 17 to 24 mass percent of high-elasticity sealants, 75 to 85 mass percent of aggregates and 0 to 8 mass percent of filling materials. The preparation method of the flexible seamless expansion joint connecting material comprises the following steps of heating the aggregates to a first preset temperature; uniformly mixing the aggregates and the filling materials to form a mixed material; heating the high-elasticity sealants to a second preset temperature; partially or totally adding the heated high-elasticity sealants into the heated mixed material; performing uniform mixing; reaching a third preset temperature; forming the flexible seamless expansion joint connecting material. The flexible seamless expansion joint connecting material has the advantages that the cost is low; the influence on operators is small; the field manual stirring is not needed; a joint connecting layer formed by the joint connecting material cannot easily generate problems of separation, cracking, tracks, pushing displacementand the like.