In UWB microwave imaging for early breast cancer detection, energy allocation to each tumor may be unequally when using single-look method, thus some of the targets may not be detected when multi-tumors exist. In this paper, we put forward a multi-look method: the source was set at eight difference places and eight groups of back-scattered signals were achieved by receiving antennas, the signals of each group were processed and results were added together. Theoretical analysis and numerical simulation show that multi-look method can not only reduce the clutters in imaging results but also detect all tumors more efficiently, and it is better than single-look method.