Abstract: A series of chemical crosslinked polycarbonate urethanes (PCUs) were synthesized from 1,4-phenylene diisocyanate (PPDI), trimethylolpropane (TMP), 1,4-butanediol (BDO) as hard segments and polycarbonate diol (PCD) as soft segments through melting prepolymer method. The effect of the content of TMP on structures and properties of PCUs were examined. The mechanical test indicated that the tensile strength and elongation at break increased with the increase of the content of TMP, while the compression set decreased. With increasing crosslink density of the PCUs, the degree of H-bonded carbonyl in the PCUs decreased from 23 % to 5 %, and the Tg value of the soft segment domains in the PCUs increased significantly form -33 °C to -17 °C, which indicated that the micro-phase separation of the PCUs was decreased. DMTA results showed that while the content of TMP was less than 40 %, PPDI-based polycarbonate urethane had excellent heat resistance and dynamic performance.