The invention discloses a refuse lac chain-extended modification powder, which comprises the following compositions in parts by weight: 100 parts of refuse dehydrated lac and 5-13 parts of multi-epoxy compound chain extending agent; by adopting macromolecular multi-functional epoxy compounds as chain extending agents, the chain extension and/or crosslinking modification reaction can be realized by performing heating reaction to carried epoxy groups with shelloic acid in the refuse lac or carboxyl and/or hydroxyl in the condensation compounds, so that the molecular weight can be increased, and further the purpose of improving the melting point of the refuse lac and increasing the relative viscosity can be achieved, the refuse lac chain-extended modification powder with the melting point ranging from 75 DEG C to 104 DEG C can be prepared, the powder can keep the dissolvability in ethanol and aqueous alkali solution while the melting point and the relative viscosity are remarkably increased, thus providing physical basis for the follow-up use of the refuse lac, and being capable of promoting the recycling of the refuse lac.