The invention provides a low-temperature mineral leaching bacterium and a low-temperature heap leaching technique of nickel sulfide ore that uses the low-temperature mineral leaching bacterium. The name of the low-temperature mineral leaching bacterium is Thiobacillus ferrooxidans Retech-L-I, the preservation registration number is CCTCC No. of M207157, the preservation date is October 16th, 2007, and the preservation unit is China Center for Type Culture Collection in Wuhan University. The low-temperature heap leaching technique of nickel sulfide ore comprises the working procedures of low-temperature mineral leaching bacterium rejuvenation, domestication and amplified cultivation, ore stacking, and spraying with a liquid containing the low-temperature mineral leaching bacterium, and a leaching liquid that is obtained by a leaching procedure is sent to working procedures of iron removing, arsenic removing and metal recycling. The low-temperature heap leaching technique of nickel sulfide ore that uses the low-temperature leaching bacterium has the advantages that the technique not only is environment-friendly, but also can be used for exploiting low-grade nickel ore resources that cannot be utilized by traditional picking metallurgy techniques, and the technique is particularly applicable to the exploit of nickel sulfide ore resources in highly cold low-temperature areas that cannot realize the engineering of biological normal temperature and high temperature heap leaching, enlarges the utilization range of nickel ore resources, and raises the synthetic nickel utilization rate.