To achieve high-precision autofocus imaging for near-field millimeter-wave radar and address the multidimensional coupling and high-order error issues caused by motion errors between the platform and the target, a millimeter-wave radar imaging algorithm was investigated based on Fourier ptychographic microscopy (FPM). The algorithm first performed range compression and range migration correction on radar echoes, then employed Fourier ptychographic imaging technology to calibrate the echo phase. The results show that using both experimental and simulated data demonstrate that the proposed algorithm significantly improves autofocus quality when processing echoes with high-order errors. Compared to traditional imaging techniques, it exhibits notable advantages in resolution and image quality while effectively eliminating phase errors induced by motion disturbances. The proposed FPM-based millimeter-wave radar imaging algorithm provides an effective solution to the challenge of high-precision imaging for millimeter-wave radar on complex maneuvering platforms, demonstrating significant application value.