The invention provides a partition type foundation pit dewatering design method considering rainfall supply. The partition type foundation pit dewatering design method comprises the following steps: determining the area of a complete partition type foundation pit and hydrogeological conditions; determining the rainfall depth; determining the total displacement of the partition type foundation pit;calculating the single well water yield; determining a construction period; determining a daily average rainfall predicted value in the construction period; calculating extra water displacement caused by rainfall supply; calculating the number of distributed wells of the foundation pi; determining a well arrangement scheme according to the well arrangement number and the foundation pit shape; andchecking the daily water pumping amount of each pumping well according to the actual rainfall. Under the condition that the construction period is determined, rainfall supply is additionally considered, foundation pit dewatering design can be conducted according to the area of the foundation pit, the dewatering depth, the corresponding hydrogeological conditions and the meteorological conditions,and a basis is provided for partition type foundation pit dewatering design. The method is simple and practical, is convenient for controlling the construction period and effectively utilizing resources, and has a great application value.