Field research was undertaken to determine how barley + legume mixtures influence nitrogen fixation and N transfer to barley. Barley + legume (main plot) and 4 different sowing rate was the experiment design. Isotope dilution was used to estimate N₂ fixation and subsequent transfer to barley. Botanical composition of legume was from 1.6% to 13.9% when harvest. Legume N derived from atmosphere ranged from minus value to 58percentage in whole plant N. N transfer amount to barley varied from 12.11㎏ to 7㎏ by different method.