Abstract: Design of different transmission systems of self-propelled forage harvester were introduced．Design characteristics of transmission systems for various components of representative self-propelled forage harvesters were analyzed．Research status of existing transmission methods were elaborated from five main aspects: chassis transmission, engine to main working components transmission, cracking transmission, feeding transmission, and header transmission．Advantages and disadvantages of various transmission methods were analyzed．It could provide reference for design of transmission system of self-propelled forage harvesters in the future．