Fine silica sand aggregate particle size in high-strength engineered cementitious composites (HS-ECC) is usually less than 0.30 mm, which is expensive and not conducive to shrinkage reduction of HS-ECC, while the mining and processing of fine silica sand has some negative impact on the environment. In this paper, geopolymer aggregate (GPA) in the range of particle size 0.30~＜4.75 mm was used as a replacement aggregate for fine silica sand to prepare HS-ECC. The particle size of GPA was divided into three groups, 0.30~<1.18 mm, 1.18~<2.36 mm and 2.36~<4.75 mm, to investigate the effect of each particle size interval on the compressive strength, tensile strain capacity and microstructure of HS-ECC. The results show that the ductility of HS-ECC is significantly improved when the particle size of GPA and silica sand is the same, but the effects on the compressive strength and tensile strength are smaller, the average crack width and average crack spacing are significantly reduced, and the width of GPA-cement matrix interface transition zone is larger than that of silica sand-cement matrix interface transition zone. When the particle sizes of GPA are different, the ductility, compressive strength and tensile strength of HS-ECC decrease with the increase of GPA particle size, the average crack width and average crack spacing increase with the increase of GPA particle size, and the width of GPA-cement matrix interface transition zone decreases with the increase of GPA particle size.