Abstract: In order to investigate the compressive constitutive relation and basic mechanical properties of alkali slag ceramsite concrete block masonry, the axial center resistance tests of 126 alkali slag ceramsite concrete block masonry specimens built with alkali slag pottery mortar were conducted. The results show that when the compressive strength of the block and the compressive strength of the mortar are the same, the peak compressive strain and ultimate compressive strain of the masonry are lower than those of the ordinary concrete block masonry because the shrinkage of alkali slag pottery mortar is large. Based on experimental results, the calculation formulas of peak compressive strain, ultimate compressive strain and elastic modulus of masonry are established with masonry compressive strength, block compressive strength and mortar compressive strength as independent variables.