Novel segmented carborane-containing polyurethane (PUR 2–5) is synthesized from hydroxyl-terminated carborane-containing prepolymer (P3) as soft segment and isocyanate-terminated carborane-containing prepolymer (P5) as hard segment by different ratio of P3 and P5. The prepared carborane-containing polyarylesters and polyurethanes (PURs) are characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). Their mechanical properties and thermal stability are measured, while the dosage of carborane biphenol is 5–10 wt %, the tensile strength is up to 20 MPa, and thermal gravimetric analyzer (TGA) curves indicate that the carborane group effectively reduces the degradation rate of carborane-containing polyurethane, which is fairly stable above 300°C and with char yield exceeding 40%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42227.