TiN coatings of different negative bias voltage were deposited on 201 stainless steel by multi-arc ion plating(MAIP). The effect of negative bias voltage on the surface microstructure, hardness, phase structure and the corrosion resistance of the coatings was investigated. Results showed that there were many droplet particles in the surface. When the negative bias voltage increased, the number and size of droplets decreased; But when the substrate bias increased to a certain value, there appeared some pits. The hardness increased at first but decreased later with the increasing of the negative bias voltage. When the negative bias voltage was-200V, the intrinsic hardness of TiN film was 2 195HV. Compared with 201 stainless steel,the corrosion resistance of TiN coatings samples was improved slightly in 3.5% NaCl solution; In l mol/L H2SO4 solution, the corrosion resistance of the-100V sample was best; Compared with untreated 201 stainless steel, the corrosion resistance of the-100V coating sample was increased 475 times.