The application and study of Rhizobium inoculation technology in groundnut (Arachis hypogaea L.) production have been performed in People's Republic of China for over 30 years. This paper summarizes the studied results during 1956-1985 when the inoculated groundnut area had increased to 2.28 million ha in China. The yield increase of groundnut generally accounted for 354 kg/ha, being equivalent to an increment of 13.4%, and the profit/input is about 40:1.Of the 1,256 experimental sites, 90.9% obtained a yield increase of above 5%, and 81.8% had an net yield increase of 150-525 kg/ha, being very significant in the statistical evaluation. Some promising strains including 009, 97-1 and C₁ have been extensively screened, field evaluaced and put to commercial inoculant production and now have an applying area of more than 0.2 million ha/year. There are chiefly two inoculant production methods: (1) liquid culture in fermentor; (2) agar surface culture scrapted and agitated into suspension. Either (1) or (2) is impregnated with partially sterilized peat carrier which contains 1-2×10⁸ ells/g.Seed dressing of inoculant is generally adopted and inoculants pelleted with gypsum, lime or rock phosphates are also used. Granular application and top dressing of inoculants may increase the yield of groundnut. Inoculation seems best suitable for sandy loam soils. Plastic sheet covering may increase the effect of inoculation. Application of 300-450 kg/ha N-fertilizer can improve nitrogen fixation and nodulation. In soils deficient in phosphorus, the effect of inoculation can be enhanced by the supplemental application of phosphate fertilizer. Also, in some cases, ammonium molybdate will increase the effect of inoculation on groundnut yield.