An A-a-B-B '(2) type monomeric unit DH was prepared based on A(2) type monomer cis-hexahydrophthalic anhydride and BB '(2) type monomer bis(2-hydroxypropyl)amine. Hyperbranched polyesteramides were synthesized by the polycondensation of DH and excess bis(2-hydroxypropyl)amine, and characterized by chemical titration, Fourier transform infrared spectroscopy (FTIR), H-1 NMR spectroscopy and gel permeation chromatography (GPC). The hyperbranched polyesteramides obtained had high molecular weights and polydispersities from 1.19 to 1.60, exhibiting narrow molecular weight distributions. The thermal behavior of hyperbranched polyesteramides was studied by thermogravimetric analysis (TG). The result showed that the hyperbranched polyesteramides synthesized had excellent thermal stability, and only 20% weight lose at 300 degrees C. The degree of branching (DB) in the hyperbranched polyesteramides was measured by high performance liquid chromatography (HPLC), and the value of DB was 0.4914.