The invention discloses an ultralow temperature preservation method and an activity identification method for a cardiocrinum giganteum var. yunnanense protoplast. The ultralow temperature preservation method comprises the steps of (1) inducing a callus, (2) separating the cardiocrinum giganteum var. yunnanense protoplast, (3) purifying the cardiocrinum giganteum var. yunnanense protoplast, and (4) freezing, unfreezing, and obtaining the preserved protoplast. The activity identification method comprises the steps of identifying activity, nursing and culturing a protoplast solid, observing division of the protoplast under a microscope, culturing for 2-3 days to see a regenerated cell wall of the protoplast, culturing for 4-6 days to see a firstly-divided cell, and culturing for 30-45 days to see a regenerated cell mass of the protoplast. With the adoption of the ultralow temperature preservation method and the activity identification method, a novel scientific approach is provided for the long-term preservation of cardiocrinum giganteum var. yunnanense which is valuable, rare and endangered and integrates viewing, edible and medicinal values.