Nitrogen fíxatíon by legumes can be valuable sources for organíc farmíng. Thís study was to ínvestígate the effect of dífferent legume mixtures on nitrogen fíxatíon and transfer to grasses on sp끼ng paddy fíeld. Three different mixtures were used (rye+haíry vetch, Italían ryegrass+crímson clover, oat+pea) in a randomized complete block design with three replications and sowed ín pots wíth different sowing rate (5:5 rye:haíry vetch,7:3=ltalian:crimson, 6:4=oat:pea) on early March. t 5NH4hS04 solutíon at. 99.8 atom%15N was applied to the each pot at the rate of 2kg N ha.1 on 16h Ap끼1. Forage were harvested at ground level ín heading stage and separated ínto legume and grass. Total N content and 15N value were determíned using a continuous f10w stable ísotope ratio mass spectrometry. DM yield of rye+vetch, Italian+crimson and 。at+pea were 6,607, 3,213 and 4,312kg/ha, respectively. Proportion of N from fixatíon was 0.73(rye+vetch), 0.42(1talian+crimson) and 0.93(oat+pea). The percentages of N transfer from legume to grass were from 61% to 24% in dífferent method by treatments and -35% to 21% in ísotope dilutíon method.