The invention relates to the technical field of building materials, in particular to the technical field of hollow building bricks, and particularly discloses an environment-friendly heat-preserving hollow building block. The building block comprises the following raw material components in parts by weight: 1 part of cement, 0.35-0.428 part of fly ash, 1.326-1.685 parts of pumice stone coarse aggregates, 1.258-1.537 parts of ferrous mine tailing sand and pumice sand mixed fine aggregates, 0.003-0.006 part of additive and 0.35-0.45 part of water. The preparation method of the environment-friendly heat-insulating hollow building block comprises the following steps: uniformly mixing and stirring all the raw material components, entering a mold for vibration molding and curing. The building brick has the advantages of being higher in compressive strength, good in heat preservation and heat insulation properties, low in preparation cost and the like and can realize the effective utilization of pumice stone resources and ferrous mine tailing sand solid wastes; the preparation method of the environment-friendly heat-insulating hollow building block is simple and easy to implement and is particularly suitable for popularization and use in the northern area of China.