Beam combiner is the key part of optical aperture synthesis telescope array. From the interferogram produced by beam combiner, the useful messages such as the central fringe phase and visibility can be extracted. With these messages, one can make it into reality to control the telescope status, compensate the path with delay lines, track fringes, beam parallel character feed back and fine control so as to get enough data used for closure phase calculating and image reconstruction. An initial result on the beam combiner for optical aperture synthesis telescope array is presented.