We design and establish a multi-resolution digital holographic microscope with optical fiber. The laser passes through the optical fiber coupler and the optical fiber splitter to form the illumination light wave and the reference light wave respectively. The illuminated light wave is collimated by expanding beam, then it passes through the sample to form object light wave. Compared with ordinary digital holographic microscope, the system is more compact and stable. And it can achieve multi-resolution quantitative phase imaging by choosing different microscopic objectives by rotating the lens turret. First, the imaging accuracy and the spatiotemporal noise of the system is measured. The imaging accuracy is verified by measuring polystyrene beads with the known parameters. The spatial noise is below 2 nm, and the temporal noise is below 0.8 nm. Then, the single-mode fiber, micro-optical elements and biological samples are measured and accurate quantitative phase images are obtained. The experimental results demonstrate that the digital holographic microscope with optical fiber illumination has high stability and can achieve accurate quantitative phase imaging.