The invention relates to low-temperature phosphate solubilization Sinorhizobium fredii and inoculant thereof. The strain name is ATHC-2, the classification name is Sinorhizobium sp., the preservation unit is the China General Microbiological Culture Collection Center, the preservation number is CGMCC No. 10651, the preservation date is March 20, 2015, and the preservation address is No. 3, NO. 1 Courtyard, Beichen West Road, Chaoyang District, Beijing. The bacterial strain ATHC-2 disclosed by the invention can resist the influence on the growth of the bacterial strain ATHC-2 by low temperature, and has high phosphate solubilization activity. Low-temperature-resistant rhizobium inoculant is used for alleviating influence on soybean nodulation and nitrogen fixation in agricultural production, improve soil fertility, reduce the use amount of fertilizer and improve the yield and the quality of crops including soybean and the like.