The invention discloses a geopolymer-based concrete for a block energy-storage tower, and a preparation method thereof. The invention aims to solve the problem that the technical requirements of highstrength, durability, high impact resistance, high weather resistance, high apparent density, self-compacting pouring, high volume stability, low energy consumption and low-carbon preparation of concrete blocks of the energy-storage tower cannot be met in the prior art. The geopolymer-based concrete is prepared from an ultrafine powder cementing material, a liquid excitant, a solid excitant, heavyaggregates, a water reducer, a retarder, water and steel fibers. The preparation method comprises the following steps: taking the raw materials; mixing and stirring the ultrafine powder cementing material, the solid excitant, the retarder and the steel fibers; adding the heavy aggregates, and performing stirring; adding the liquid excitant, the water reducer and water, and performing stirring; and molding the obtained mixture by a layered loading and layered vibrating process, and maintaining the molded mixture at normal temperature for 28 d. The preparation method utilizes a large amount ofsolid wastes, has energy-saving and environmentally-friendly properties, is suitable for preparing the concrete blocks of the energy-storage tower, and has good economic and social benefits.