[Objective] Longitudinal ridge slope soil erosion process was studied by using non-rige slope as control in order to provide scientific basis for the prevention and control of soil erosion in the northeast mollisol region slope. [Methods] Simulated rainfall experiments were conducted. The experimental treatments included two tillage measures (longitudinal ridge and non-ridge tillage), three rainfall intensities (50, 75 and 100 mm/h) and one slope gradient (5°, which was the critical slope gradient for changing longitudinal ridge to contour cultivation). [Results] Compared with non-ridge tillage, the total runoff rate and total erosion amount of the longitudinal ridge tillage increased by 1.2~1.7 times and 1.3~2.1 times, respectively. The runoff and sediment process also changed. Compared with non-ridge treatment, the concentrated runoff velocity in furrows of the longitudinal ridge increased by 1.0~2.3 times and shear strength increased by 0.7~1.2 times. Consequently, hillslope erosion pattern shifted from sheet erosion dominant to rill erosion dominant, and rill erosion occupied 55.3%~65.6% of total erosion amount at longitudinal ridge treatments. [Conclusion] The increase of runoff velocity and occurrence of rill erosion were two main reasons for the intensification of hillslope erosion at the longitudinal ridge treatment.