Abstract: The MUSER (Mingantu Ultrawide SpEctral Radioheliograph) is a new generation of solar dedicated radio telescope for imaging the Sun at high time, high spatial and high frequency resolutions simultaneously. It is an aperture-synthesis telescope, so the amplitude and phase are the key factors in the final imaging. The phase pattern is an important factor affecting the array's amplitude and phase. In this paper, allowing for the techniques of MUSER, the method by measuring correlation is adopted to measure phase pattern of feeds for MUSER based on aperture synthesis principle. Since MUSER has numbers of antennas and located in harsh environments and according to the demand of astronomical observations, the performance of the antennas should be measured frequently. This method simplifies the process of phase pattern measurement of the interferometric array and it can obtain accurate results efficiently. The measuring process and analysis of MUSER-I are presented in detail in this paper. In addition, to support future scientific observation, the phase pattern's effect on the image is further studied.