The invention discloses a hydration degree measurement method for cement-based materials based on nuclear magnetic resonance, which belongs to the technical field of cement material measurement. The hydration degree measurement method disclosed by the invention adopts a nuclear magnetic resonance technique to test nuclear magnetic signals of the cement-based materials at different ages; a relation between transverse relaxation time and the nuclear magnetic signals is obtained by inverse analysis; furthermore, a ratio of nuclear magnetic semaphores of left and right peaks is taken as a nuclear magnetic signal ratio of gel pore water and capillary pore water, and then the hydration degree of the cement-based materials to be detected at the age is solved according to a Powers model. Compared with traditional methods including a muffle furnace method and the like, the hydration degree measurement method disclosed by the invention is a nondestructive testing method, can reduce operation steps of a test greatly and shorten a testing period greatly, and can be used for monitoring samples continuously so as to ensure that the errors of test results are small; meanwhile, the method disclosed by the invention does not need to calibrate nuclear magnetic resonance semaphores and sample water content and directly adopts the ratio of the nuclear magnetic semaphores of the left and right peaks, namely a microstructure factor, as a parameter to represent the hydration degree, and therefore, measurement procedures and errors are reduced.