The utility model discloses a negative polar lug for a cell of a soft-packaging lithium-ion power battery, which comprises a main body of the polar lug, wherein the main body of the polar lug is formed by compounding nickel and copper, or is simply formed by the copper, and one end of the polar lug is also provided with a branch of a nickel piece in an extending way on the basis of the main body. The polar lug disclosed by the utility model has high electric conductivity. When large current passes through the polar lug, the temperature rise is lower, and the safety performance of the power battery is enhanced. Meanwhile, the novel negative-pole polar lug which is simple and convenient to operate and has strong practicability can be provided to the soft-packaging lithium-ion power battery coiled with stacking pieces.