Abstract: In order to overcome the limitation of ABAQUS in simulating rainfall infiltration, Python language is used to modify the rainfall infiltration boundary in ABAQUS, the rainfall boundary is considered as an uncertain boundary and is solved by iterative algorithm, and then a rainfall module is developed. This module overcomes the unchanged infiltration rate which is adopted in ABAQUS, thus the ABAQUS’s function in rainfall infiltration analysis is improved. Compared with the column infiltration tests, the validity of this module is confirmed. On this basis, the rainfall infiltration process of anti-slide pile slope is studied. The results show that the anti-slide pile can improve slope stability, however, under rainfall conditions, the anti-slide pile will reduce the effective drainage section, the underground water from trailing of the slope cannot discharge in time, and this will have adverse effect on the slope stability. So, for pluvial regions, the adverse effect of rainfall should be considered in anti-slid pile design. With the aid of the powerful features of ABAQUS, the proposed module may provide a good research platform for more complicated rainfall problems in the future.