Disclosed is a method for preparing a semi-furanic copolyamide containing at least one furanic dicarboxylic acid moiety and at least one aliphatic diamine moiety in the backbone. The method is based on solid-state polymerization. Particularly, the method uses a biomass-derived furanic dicarboxylic acid as a raw material. A semi-furanic copolyamide prepared by the method has molecular weight and color levels that are practically required in industrial applications. In addition, the semi-furanic copolyamide can replace fossil fuels due to its good thermal stability and is suitable for use as an environmentally friendly bioplastic.