The invention discloses a rotary encoder terminal transmission connection structure which is connected with a mandrel of a rotary encoder. The transmission connection structure comprises a rotating disc, a connection disc and a plurality of ball bodies, wherein the ball bodies are contained in the position between a first recess of the rotating disc and a second recess of the connection disc, and all the ball bodies are jacked and pushed by a spring to move within a preset range. Therefore, the rotating disc and the connection disc can be quickly disassembled and assembled, and the effect that the rotary encoder precisely senses the rotating position can also be ensured.