[Objective] Revealing the slope erosion of Yunnan laterite as dependent variable caused by independent variables of rainfall intensity, slope gradient, slope length in order to provide bases for the prevention and control of soil erosion in Yunnan laterite area. [Methods] Artificial rainfall erosion was simulated indoor and analyzed theoretically. [Results] (1) The slope erosion of Yunnan laterite could be regressed significantly with rainfall intensity, slope gradient, slope length(R²>0.95). (2) Under certain slope gradient and length, the slope erosion modulus of laterite had power function relationship with rainfall intensity as independent variable. (3) Under certain rainfall intensity and slope length, the slope erosion modulus of laterite had a quadratic polynomial relationship with slope gradient. (4) Under certain rainfall intensity and slope gradient, the slope erosion modulus of laterite had a quadratic polynomial relationship with slope length. [Conclusion] The slope erosion modulus of Yunnan laterite increased with the increase of rainfall intensity. When the slope was less than the critical slope 21.4°, slope erosion modulus increased with the increase of slope. When the slope is greater than the critical slope 21.4°, slope erosion modulus decreased with the increase of slope. The slope erosion modulus increased with the increase of the slope length.