The application of metal niobium for making niobium capacitor in electronic industry was introduced, and the original, background, history and current state for development of niobium capacitor were described. The stability of dielectric film has influence on performance of niobium capacitor. A better result was finally obtained through comparative experiments on the dielectric film formed electrochemically. The result shows that the stability of niobium pentoxide dielectric film is greatly improved by optimizing process conditions such as type of formation solution and formation time. As a result, the performance of niobium capacitor is effectively controlled and improved, thereby solid niobium capacitor equivalent to tantalum capacitor at performance can be manufactured, and has potential for industrialization application.