The invention discloses a sintered neodymium iron boron permanent magnet surface nitride composite deposite and a preparation method. The nitride composite deposite is composed of two or three layers.The two layers comprise titanium in the inner layer and a nitride clad layer in the outer layer. The three layers comprise titanium in the inner layer, an intermediate layer and the nitride clad layer in the outer layer; the inner layer is 1-5[mu]m thick and the intermediate layer and the outer layer are separately 5-30[mu]m thick; and the intermediate layer and the outer layer are titanium nitride clad layers or titanium nitride cladded aluminum. The preparation method comprises the following steps: cleaning and drying a sintered neodymium iron boron matrix by employing magnetron sputteringion plating equipment; putting the matrix in a vacuum chamber to be vaccumized; introducing argon for ion bombardment cleaning; adjusting the nitrogen proportion to deposit the clad layer; and after the temperature in the vacuum chamber is reduced to the room temperature, taking out the magnet. The preparation method is environment-friendly in preparation process, pollution-free and stable in process, and the obtained neodymium iron boron permanent magnet surface clad layer can be colorful, the bonding force of the matrix and the clad layer is good, and the corrosion resistance of the sinteredneodymium iron boron permanent magnet can be improved obviously.