The invention discloses a four-byte framing method suitable for a JESD204B protocol, and the method comprises the following steps: step1, a three-level mapping mode is adopted to caching samples of a plurality of periods; step2, present working mode is judged according to different combinations of L, M, S, F parameters; and step3, cached sample data is combined as frame data of corresponding structure according to present working mode information. According to the invention , the method fills the blank of domestic relevant researches and has universality, all framing modes based on the JESD204B protocol can derive correct frame structures through the method, when combination modes of a plurality of specific framing structures adopted by a chip is determined, an one-level-simplified mapping realization scheme based on the method can be provided.