Digital holographic microscopy can measure quantitative light field information, but holographic phase reconstruction usually requires spectral filtering, analog diffraction, phase unwrapping, distortion compensation and other steps, and the size error of the manually selected filter window will greatly affect the filtering, image quality. A one-step digital holographic phase reconstruction method based on DeepLabV3+ network is proposed. The method introduces MobileNetV2 structure on the basis of DeepLabV3+ network for improvement. Firstly, MobileNetV2 is used to extract hologram features, and then multi-scale features are fused through hole space pyramid pooling. Finally, bilinear interpolation method is used for upsampling to obtain high-precision quantitative phase reconstruction results. The experimental results show that compared with the reconstruction using PhaseNet, the method improves the structural similarity index by 6.5%, and can accurately and efficiently realize the high-precision quantitative phase reconstruction of digital holography.