As one of the important surface coverings in arid and semi-arid regions, biocrusts can promote the restoration and stability of ecosystems by stabilizing soil surface to resist soil erosion and degradation. However, the specific mechanism of this process needs to be further studied. In order to investigate how biocrusts improve soil physical properties and thus water and soil conservation, we measured the soil pore characteristics and penetration resistance of biocrusts and bare soil using high-resolution X-Ray computed tomography (CT) scanner and high-precision soil penetrator in the Loess Plateau. In addition, structural equation model (SEM) was established to analyze the effect pathway of biocrusts on soil porosity and penetration resistance. The results showed that moss-dominated biocrusts changed soil pore characteristic parameter, and significantly increased the total soil porosity of 0-2 cm layer (p＝0.01). Compared with bare soil, the total soil porosity of moss-dominated biocrusts on aeolian sand and loess soil increased by 1.62 and 2.12 times, respectively. Moreover, the porosity of moss-dominated biocrusts decreased exponentially with the increase of soil depth. The plane porosity of moss-dominated biocrusts was significantly higher than that of bare soil (p＜0.001), both of them decreased sharply within 0-1 cm. The penetration resistance of moss crusts improved with the increase of soil depth, but obvious mutation of penetration resistance was found in the middle of crust horizon, while it basically stabilized in the subcrusts layer. On both aeolian sand and loess soil, the plane porosity and penetration resistance of moss crusts were log negatively correlated, and they were linearly positively and log negatively correlated in bare soil, respectively. The effect of biocrusts on soil penetration resistance was mainly realized through indirect ways such as particle composition and porosity. In Loess Plateau, moss crusts significantly increase the penetration resistance of topsoil through indirect means such as changing porosity and particle composition, which was conducive to improving soil surface stability and providing strong conditions for regional soil and water conservation and ecological restoration.