Pulsed magnetic treatment (PMT) is a convenient, efficient and green posttreatment method, which utilizes magnetic fields to improve the properties of metal materials. In order to study the effect of PMT on the mechanical properties and microstructure of pure nickel (Ni), and to reveal the potential influence mechanism of PMT on ferromagnetic materials, the pure Ni samples were treated with pulsed magnetic fields at different magnetic intensity, and the mechanical properties and microstructure were analyzed before and after the treatment. The experimental results show that the hardness of Ni samples was decreased by PMT of 0.5-1.5 T, with a minimum decrease of 0.36% at a magnetic intensity of 1.5 T. For tensile properties，the maximum increase in tensile strength and elongation was obtained at a magnetic pulse strength of 1.5 T, with increases of 4.19% and 1.65% compared to the untreated one, and with little change at 0.5 and 1.0 T. Changes in the distribution of defects in Ni samples were observed in the microscopic characterization. The dislocations at the grain boundaries moved into the grain cells, forming the aggregation of small dislocations and incomplete dislocation cell walls, and the change of the microscopic defects improved the tensile properties of the pure Ni samples.