The invention relates to a mass concrete mixture and a construction method of pouring a wall body by the mass concrete mixture. The technical scheme adopted by the invention is that the mass concretemixture is prepared from the following raw materials in parts by weight: 165 parts of water, 214 parts of portland blast furnace slag cement, 743 parts of sand, 1070 parts of gravel, 103 parts of flyash, 95 parts of mineral powder, 4.94 parts of admixture and 0.9 part of polypropylene fibers, wherein the admixture is prepared from a JH-GHL polycarboxylate superplasticizer, an H-III type concrete mortar water-proofing agent, a UEA-H type concrete expanding agent, basic aluminum acetate and delta-aluminum oxide of which the weight ratio is 4 to 3 to 2 to 0.2 to 0.3. The construction method comprises the steps of pre-construction preparation, weighing of the raw materials, stirring of the raw materials, pouring, vibrating, primary leveling, maintenance, secondary leveling and measurement of the temperature. In the construction process of a mass concrete structure, indwelling of a post pouring belt can be avoided, the construction progress is speeded up and the construction period is shortened; in addition, without structural cracks, the overall stability of the structure is improved and the waterproof quality of a project can be ensured.