The invention relates to acinetobacter calcoaceticus X.L.Zhu.SGD07-3-16 with free living nitrogen fixation capability. The acinetobacter calcoaceticus is preserved in China general microbiological culture collection center, and the preservation number of the acinetobacter calcoaceticus is CGMCCNo.5455. The acinetobacter calcoaceticus is high in nitrogenase activity and phosphorus and potassium dissolving capability, and has ACC (1-aminocyclopropane-1-carboxylic acid) deaminase activity, a certain amount of indoleacetic acid can be generated, and the generation of siderophore is avoided; when an acinetobacter calcoaceticus-containing liquid or solid microbial agent is used for inoculating crops such as corns, oilseed rapes and leaf mustard, the growth of the crops can be remarkably promoted, and the yield of the crops can be increased.