Water deficit is a key abiotic factor that limits plant growth and development, and inhibits nitrogenase activity of Rhizobium in Fabaceae family including peanut (Arachis hypogaea). Peanut improvement for drought tolerance is critical for the future of crop production in arid and semi-arid regions. We are interested in the effects of the interaction of water stress and nitrogen fixation on the growth and yield of peanuts under a conventional field. The objectives of this study were to examine the relationship between nodulation, nitrogen-fixation, and trigonelline concentration, and to evaluate potential biological roles of trigonelline on symbiosis efficiency and growth characteristics. Ten peanut genotypes were used in this study. One hundred and eighty plots, 90 for full irrigation and the rest for partial irrigation (50% irrigation), were prepared in the randomized complete block design. Each plot length was 152.0 cm with a 60.8 cm alley between any two consecutive plots. Two different strains of Rhizobium spp. were used to inoculate the peanuts. Our results showed that a mean pod yield and plant biomass in the fully irrigated plot were 4739.8 kg ha-1 and 8158.1 kg ha-1, respectively, while those in 50% irrigated plot were 4136.2 kg ha-1 and 6508.3 kg ha-1, respectively. Mean pod yield and biomass were significantly (P<0.05) different for two plots in this study. Grain yield in two Rhizobium inoculated plots was significantly greater than non-inoculated plots. Numbers of nodule were significantly correlated (r = 0.41, P<0.05) to the efficiency of nitrogen fixation. Other results will be reported later.