Biomass, N derived from BNF, total N and Ndfa % of different part tissues of pea plants inoculated with various Rhizobium. leguminosarum strains were determined. Particularly identified were whole plant biomass correlated with N derived from BNF. The significant direct correlations between biomass and N derived from BNF indicated that N-fixation efficiency of strains are important factors influencing biomass accumulation of plants, but not the sole factors determine the promoted capacity of strain on plant biomass production. Different strains show various performances on accumulation of biomass in different parts of plant tissue, R. leguminosarum SY12 performed best on promotion of kernel production. In order to obtain aimed strain with particular property such as promotion of kernel production, the 15N tracing technique can be used in R. Leguminosarum strains screening of R. Leguminosarum, but the analysis both separate part and whole plant tissue are necessary.