Rainfall is considered as a dynamical factor causing the soil erosion, and rainfall erosivity can reflect the potential ability of soil erosion by rainfall. So the accurate calculation of rainfall erosivity is an important process for quantitative forecast soil erosion. In this paper, the research actuality and progress of rainfall capacity and erosivity, raindrop spectrum measurement, the calculation methods for rainfall capacity and erosivity, the relationship of rainfall and sediment were summarized. Furthermore, the calculation formulas of rainfall erosivity and capacity that are suitable in China were proposed according the regionalism characteristics of rainfall.