In recent years, cylindrical millimeter-wave (MMW) holographic imaging technique has attracted a lot of attention for its special advantages, including high resolution, large aperture, and strong penetrability. A modified wavenumber-domain three-dimensional imaging algorithm applied for near-field cylindrical MMW holography is proposed. The core of the proposed algorithm is to generate an accurate and efficient phase compensation factor in wavenumber-domain. Compared with the existing algorithms, the proposed algorithm holds advantages in both imaging speed and imaging quality and is more suitable for security inspection application. Both the simulation results of point targets and the experimental results of the resolution test panel validate the effectiveness of the proposed algorithm.