Multimode fibers (MMFs), capable of supporting thousands of optical modes within a hundred-micrometer-scale diameter, exhibit unique advantages in imaging applications, including compact size, high resolution, and exceptional flexibility. Particularly in medical endoscopy, MMF-based endoscopes can access narrow cavities to realize submicron-resolution in vivo imaging with minimal tissue damage, demonstrating significant potential in brain science research and disease diagnosis. Light field modulation technologies combined with methodologies such as digital phase conjugation, transmission matrix analysis, compressed sensing, and deep learning effectively address the highly disordered light fields caused by mode dispersion and mode coupling during MMF transmission. To address the critical challenge of bending-induced mode distortion, researchers have proposed a series of MMF bending correction techniques. In this paper, we systematically review the advancements of MMF imaging across diverse fields, including in vivo endoscopic imaging, nonlinear optical effects, and multimodal integrated imaging. Finally, we summarize the challenges facing multimode fiber imaging technology and provide an outlook on future directions.