The invention discloses a non-uniform graph search partitioning algorithm used for renal cortex positioning. The algorithm is characterized by comprising steps of (1), defining a multi-scale boundary function when segmentation starts so as to realize non-uniform sampling on nodes; (2), defining different weights according to characteristics of renal cortex during segmentation and using a max-flow/minimal-cut algorithm for detecting an optimal surface for segmentation. The segmentation speed is high and the segmentation accuracy is high according to the invention.