Red clay has the undesirable properties such as softening and disintegration when encountering water, and its slopes are damaged by long-term erosion, often resulting in soil erosion. In the recent years, the microbial soil improvement technology has emerged, and the application prospect is promising. In this study, the disintegration test of microbial-magnesium oxide cured red clay and the slope erosion model test was conducted to compare the disintegration rate of vegetative soil and cured soil under dry and wet cycles, and the slope morphology and erosion rate of vegetative soil and cured soil slopes under a single rainfall condition and under dry and wet cycles. The results showed that the disintegration rate of the vegetative soil was accelerated under dry and wet cycles, but had little effect on the disintegration of the cured soil; the erosion rate of cured slopes was only about 2.8% of the erosion rate of the vegetative soil slopes under single rainfall conditions; under dry and wet cycles, the erosion rate of the vegetative soil slopes decreased and then increased with the increase of the number of dry and wet cycles, while the erosion rate of the cured soil was extremely small. The curing effect of microorganisms-magnesium oxide on red clay is good, and the research results are of guiding significance for the practical application of cured red clay in open-pit mine slopes and other projects.