A method for processing textile fibers is provided. The method comprises: adding a plurality of raw materials for processing textile fibers into a plurality of kettles; preparing supercritical carbon dioxide; obtaining one or more natural plant dyes and one or more natural plant extracts from the plurality of raw materials, and dissolving the one or more natural plant dyes and the one or more natural plant extracts in the supercritical carbon dioxide; dyeing and functionally modifying the textile fibers simultaneously by using the supercritical carbon dioxide carrying a mixture of the one or more natural plant dyes and the one or more natural plant extracts; performing a post-process to recycle the supercritical carbon dioxide; and performing a cleaning process to clean the one or more natural plant dyes and one or more natural plant extracts.