In order to correct the piston phase error of the corner cube reflector (CCR) array, a multi-element one-dimensional phase precise adjustment mechanism was designed, and a method of piston phase error detection and adjustment based on the coherent synthesis principle was proposed. Firstly, a mechanical device was designed to adjust the phase of a single corner cube reflector. Then, based on the principle of far-field imaging, the influence of piston phase error on far-field diffraction imaging was analyzed. Secondly, based on the difference of far-field facula, a method of measuring and adjusting the piston phase error of pyramid array was proposed. The experimental results show that the phase precise adjustment mechanism of the CCR array can achieve the adjustment accuracy of 0.1 μm level. By observing the far-field image of the reflected beam of the CCR array, adjusting the relative position of the CCR array, the PIB of the reflected beam is raised to 0.49, and the far-field image is close to the results of simulation. The piston phase error correction of the sub aperture of the CCR array is basically realized, and it improves the use efficiency of CCR array and expands the use scenarios of CCR array.