Abstract: By means of the single-factor compressive strength tests, X-ray diffraction (XRD) tests and scanning electron microscope (SEM) tests, the variation rules of strength and microscopic morphology of the activated magnesium oxide (MgO) carbonized raw earth blocks under the influences of different material contents and water contents are studied. The results show that when the mixture ratio of raw materials of the active MgO-carbonized raw soil blocks is 7:7:6:80 MgO: cement: fly ash: raw soil and water is added according to the optimal moisture content of raw soil substrate, the compressive strength of the blocks prepared is higher, and the 21-day compressive strength tends to be stable, with an average value of about 7~8 MPa. The XRD and SEM tests show that the strength, cementing property and pore filling of magnesium-type carbonate generated by hydration and carbonation reaction of the active MgO cement are the main reasons for the increase of strength of the blocks.