The invention discloses an early strength concrete for power transmission line foundation construction, and a preparation method thereof, and relates to the field of concrete for roads in order to solve the problems of low early strength and long curing time of power transmission line cast-in-place concrete in the foundation construction process. The early strength concrete comprises, by weight, 360-500 parts of sulfoaluminate cement, 1700-1880 parts of aggregates, 0.108-0.5 parts of triethanolamine, 1.44-12.5 parts of a polycarboxylic superplasticizer and 108-225 parts of water. The concrete is prepared from sulfoaluminate cement, so a disadvantage that about 3-7 days are needed by ordinary portland cement reaching 70% strength is solved. The slump is 160-200mm, foundation construction requirements are met, and the durability is improved; the initial setting time is prolonged 1h, so the early strength concrete is suitable for onsite production, and is also suitable for being pumped; only 1d is needed when 30MPa compressive strength is reached, so rapid construction is convenient; and the frost resistance of the early strength concrete is high.