The AB3 type hyperbranched poly (amide-ester) was synthesized by the condensation polymerization reaction of hexahydrophthalic anhydride and tri(hydroxymethyl) aminomethane. The conversation ofmonomer can reach 80%.Reaction conditions (time and temperature) have been investigated systemically. The dynamics of condensation polymerization reaction for the AB3 type hyperbranched poly(amide-ester) was studied as well. Another, the equation of the overall polymerization rate can be written as follows: polycondensation reaction is a third-order and self-catalyst process, the overall activation energywas calculated to k=Â1.12×104, Ea= 93.07 kJ/mol. The proof of poly-condensation was obtained from FTIR spectroscopy. And the hyperbranched polymer was charactered by intrinsic viscosity and TGA analysis. The result showed that the hyperbranched polymer have low melt viscosity, good dissolubility and good thermostability.