The invention discloses a dyeing method of a natural fiber. The dyeing method comprises the following particular steps of firstly, adding natural vegetable dye, liquid carbon dioxide and a color fixing agent into a supercritical carbon dioxide dyeing device, heating, and maintaining for a certain time; afterwards, adding the natural fiber into the supercritical carbon dioxide dyeing device, dyeingat and under certain temperature and pressure, and maintaining for a certain time; next, relieving the pressure, cooling to a normal temperature and depressurizing to normal pressure to obtain a preliminarily dyed natural fiber; treating the preliminarily dyed natural fiber, afterwards, adding into the supercritical carbon dioxide dyeing device, dyeing at and under certain temperature and pressure, maintaining for a certain time, and then relieving the pressure to obtain a finished-product dyed natural fiber. The dyeing method, through a two-step dyeing method, is used for realizing printingand dyeing the natural fiber by natural dye, and further, does not need pretreatment, and the dyeing method has advantages of good environmental protection effect, water resource conservation, good color fixation effect and the like.