The invention provides an electro brush plating Ni-Fe alloy plating layer, and a bath solution, a preparation method and functions of the plating layer: The grain size of the plating layer is 10 to 30nm, with Fe 5 to 20percent (weight percent), thickness 10 to 100Mu m and hardness HV450 to HV650; the components of the bath solution include nickel sulfamic acid, nickel chlorite, ferrous chloride, succinic acid, boric acid, acid citrate, cevitamic acid, saccharin and sodium dodecylsulphonate; the invention is prepared with the electro brush plating metho, with the soluble metal Ni as the anode, and is applicable in repairing of abraded parts and surface strengthening of parts of new products. The invention improves the hardness of common Ni-plating layer by alloying of Fe, so as to improve the wear resistanceand saves partial Ni; the soluble anode Ni electro brushing plating preparation method solves deficiencies of common graphite anodes, such as bringing pollution to the bath solution, low deposition speed, short service life of the bath solution, etc; the plating layer has advantages of low stress and no crackle, so that the anti-corrosion resistance performance is quite high.