Abstract: Abstract：Objective To investigate the effectiveness of the Nucleated Red Blood Cells’ enrichment by intervening membrance ionic channels- K+/Cl- cotransporter and density gradient centrifugation in umbilical cord blood. Methods Setting up optical Intervening condition of maximal change of cell volume from RBCs on the umbilical cord blood, these rates of cell’s enrichment by different density medium centrifugation were determined by flow cytometry. Results Compared to traditional rich method, the average purity of NRBC enrichment in the umbilical cord blood could take from 8.6% to 69.9% and 55.9% by centrifugation of 1.065g/L medium after intervening and 1.099g/L medium,which means to respectively increase about .8 and 6.5 times enrichment of NRBC. Conclusions Both urea intervention and density centrifugation could effectively promote the rate of the NRBC’enrichment .