The invention discloses 2,5-furan dicarboxylic acid based polyamide with a full biomass source and a preparation method thereof, and belongs to the technical field of bio-based polyamide. The structural formula of the 2,5-furan dicarboxylic acid based polyamide is shown as (I), and in the formula, R is alkylene of C4, C5, C6 and C10. According to the method, 2,5-furan dicarboxylic acid and aliphatic diamine are used as raw materials, and 2,5-furan dicarboxylic acid based polyamide is prepared through a salt forming-pre-polycondensation-solid phase polycondensation process. 2,5-furan dicarboxylic acid and aliphatic diamine monomers are derived from biomass resources. The raw materials are wide in source, rich in reserves and renewable, and can be used as supplementation and partial substitution of non-renewable fossil raw material monomers, so that the high-performance environment-friendly polyamide is synthesized, is used in the fields of fibers, high-performance engineering plastics and the like, and has important scientific significance and application value.