The present invention discloses a hemp fiber degumming boiling-off additive, a preparing method and the application thereof. The invention is characterized in that the additive is composed of two parts of organic surfactant and inorganic boiling-off additive. The additive I and the additive II are prepared through compounding the organic surfactant and inorganic boiling-off additive. Furthermore the additive I and the additive II are applied for the chemical degumming of raw hemp ramie. When the additive I and the additive II according to the invention are applied to the industrial process of chemical boiling-off degumming, not only are the xylogen content and residual adhesive rate reduced, but also the degumming effect is increased. Furthermore the boiling-off time is shortened. The dosage of NaOH and the discharge amount of polluted wastewater are reduced. Additionally, the adding of the additive according to the invention increases the whiteness and plasticity of degummed ramie. The hemp fiber degumming boiling-off additive has excellent application value.