Dynamic magnetic resonance imaging methods and devices are provided. According to an example, a method includes: collecting respective k-space data for each of imaging phases by scanning a part of a subject via an equidistant undersampling manner, determining basic k-space data for the part of the subject, determining respective differential k-space data for each of the imaging phases based on the respective k-space data for each of the imaging phases and the basic k-space data, obtaining a basic image based on the basic k-space data, determining a respective sparse image for each of the imaging phases, reconstructing a respective differential image for each of the imaging phases from the respective differential k-space data for the imaging phase, and obtaining a respective magnetic resonance image for each of the imaging phases based on the respective differential image for the imaging phase and the basic image.