A complete partitioned foundation pit dewatering method comprises the following steps that (1) the complete partitioned foundation pit area and hydrogeological conditions are determined; (2) the dewatering depth is determined; (3) the partitioned foundation pit total displacement is determined; (4) the single well water yield is computed; (5) the construction period is determined; (6) the number of foundation pit wells is computed; and (7) a well arrangement scheme is determined according to the number of the foundation pit wells and the foundation pit shapes, and pumping equipment and materials which are required by construction are prepared. According to the complete partitioned foundation pit dewatering determination method, under the condition that the construction period is determined, foundation pit dewatering design can be conducted according to the foundation pit area, the dewatering depth and the corresponding hydrogeological conditions, and bases are provided for partitionedfoundation pit dewatering design. The method is simple and practical, the construction period is conveniently controlled, the resources are effectively utilized, and the method has quite high application value.