The invention relates to a Ni-Fe-Nd-P bath and a glass fiber Ni-Fe-Nd-P alloy and a preparation method thereof, which is characterized in that a formula of the bath comprises nickel sulfate, sodium hypophosphite, ferrous sulfate, neodymium nitrate, sodium citrate, malic acid, butane diacid, ammonium sulfate, distilled water, thiourea, urea and concentrated hydrochloric acid; the preparation methodcomprises the following steps: main salts, namely, the nickel sulfate and the ferrous sulfate are put in the distilled water, added with the neodymium nitrate, the distilled water and the concentrated hydrochloric acid after dissolution, and then added with sodium citrate, malic acid, butane diacid, ammonium sulfate, sodium hypophosphite, thiourea and urea in sequence for dissolution and then added with ammonia to prepare the bath. A chemical plating technology is utilized to prepare the glass fiber Ni-Fe-Nd-P alloy. The beneficial effects are that as a right amount of neodymium nitrate is added to the chemical bath, the content of phosphorus in a prepared alloy coating is 5 percent to 10 percent; the glass fiber which adopts the chemical plating has good electrical conductivity and can be used as a conductive filler and an electric loss absorbent.