DOI: 10.7764/RDLC.18.2.375 Loess is a kind of common and important building materials in civil engineering. Particle size distribution has a significant effect on loess engineering properties and there are many studies in this filed. Due to the chemical cementation and the molecular attraction in the loess, the particles are usually gathered together and appear in the form of conglomerations. The conglomeration is much larger than the particle and easy to crush. The study on the influence of conglomeration gradation on the engineering properties of loess is relatively less and needs to be enriched. In view of this, the loess samples with different conglomeration gradations are prepared, and the compaction test, compression test and direct shear test are carried out. The test results show that the conglomeration gradation has a certain effect on the maximum dry density and shear strength of loess. But the effect on compression test is not significant. The better loess conglomeration gradation is, the better its engineering properties are. The engineering properties of loess with larger conglomerations are better than those with smaller conglomerations. The reason is related to the breakage of loess conglomerations after loading. The test samples are also observed by stereomicroscope, and the results of mesoscopic observation are consistent with the macroscopic phenomena. Therefore, reasonable adjustment of loess conglomeration gradation is beneficial to obtain better engineering properties.