通过36 组强度等级分别为M30、M50 和M80 且边长分别为70 mm、100 mm、150 mm和200 mm的水泥砂浆立方体试件的抗压试验，研究了不同强度等级水泥砂浆试件抗压强度的尺寸效应，建立了强度等级与抗压强度尺寸效应的关系，提出了水泥砂浆抗压强度尺寸效应率的计算公式，通过试验数据验证了该公式的适用性。

The dimensional effect of mortar cubic compressive strength was investigated through compression experiments on mortar cubic specimens with the strength grade M30, M50 and M80 and specimen side length of 70 mm,100 mm,150 mm and 200 mm. The relationship between the strength grade and dimensional effect was built in this paper. Furthermore, the computational equations of dimensional effect were proposed. Finally，good agreements were found between tested data and the computational equations.