Abstract: The interference of two point sources is analyzed accurately. The interference pattern and the separation of adjacent bright fringes on different sections are described. And it is found that the separation is the function of the interference order, the wavelength, the source distance, and the observation points. The computer simulation results are given also. These results also work for the interference of other kinds of coherent source.

Key words: interference of point coherent sources, hyperbola family, hyperboloid family, interference pattern, fringe separation