The invention relates to a multi-pipe quantitative medium filling system of a supercritical fluid waterless dyeing machine. The system comprises a supercritical fluid medium reservoir, a stop valve, and a medium filter sequentially connected by a high-pressure main pipe, and at least two filling branches independent of each other and connected to the medium filter. Each filling branch includes a booster pump, a supercritical fluid high-pressure mass flowmeter, a ball valve, and a dyeing unit sequentially connected along a medium forward direction by a high-pressure branch pipe. By using a mass-measurement filling system having multiple branches independent of each other, the invention can effectively realize simultaneous and accurate quantitative medium filling for separate dyeing units and differentiated filling for dyeing units with different medium masses, thus overcoming disadvantages such as unreliability, inaccuracy and low use efficiency of a conventional method, and also making a dyeing operation simple and scientifically feasible.