Combining coherent laser beams is an important and challenging area of laser science and is now still in a state of laboratory. We have succeeded in the coherent combination of three-element fiber-laser array based on ytterbium-doped polarization-maintaining single-mode power amplifiers with good experimental results. In this paper, we introduce the experimental setup and detailedly describe the method of measurement and control of phase noise. A single signal arm is taken as example, the measured phase noise are presented. At last, we give the results of coherent combination in the far field and briefly discuss a few factors having effect on the far field properties. We conclude that the combining method can be scaled to a large number of lasers.