Due to the influence of the depth of focus, two-dimensional single frequency cylindrical surface imaging systems cannot accurately compensate all the scattering points of the body target. In order to solve the problem of the limited depth of focus, a focus enhancement algorithm based on image fusion is proposed. Using the fusion processing of the imaging results of different cylinders, the focused image is finally obtained. It can be seen from the comparison with the original image that the proposed method effectively solves the out-of-focus problem caused by the compensation of the phase mismatch due to the limited depth of focus.