A series of different mole ratio of hybrid isocyanate based polyurethane was successfully synthesized via step-by-step polymerization, with isophorone disocyanate (IPDI)/two phenyl methane diisocyanate (MDI) and polytetramethylene ether glycol (PTMG-2000) used as raw materials, dibutyltin dilaurate (DBTDL) as the catalyst, 1,4-butanediol (BDO) as the chain extender and anhydrous ethanol (EtOH) as the blocking agent. The prepared polyurethane was diluted and dispersed with a dispersing machine, and then prepared the polyurethane film. The solid content of the prepared polyurethane was measured; the mechanical properties and the yellowing resistance and UV transmittance before and after ultraviolet aging of the polyurethane film were measured too. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and thermal analysis (TG) were used to characterize the structure and properties of the polyurethane film. The results showed that with the decrease of n(IPDI)/n(MDI), the yellowing resistance of polyurethane film decreased, but its breaking strength increased from 18.73N of IMPU-6 to 42.85N of IMPU-11, as well as the elongation at break was reduced from 763.44% of IMPU-1 to 463.85% of IMPU-11. The color difference before and after UV aging increased from 0.72 in IMPU-1 to 22.92 in IMPU-11, and the yellowing grade decreased from grade 5 of IMPU-1 to grade 1 of IMPU-11. Meantime, the UV transmittance decreased from 89.74% of IMPU-1 to 35.04% of IMPU-11, the crystallinity increased from 2.02% of IMPU-1 to 11.27% of IMPU-11, the residue at 450℃ increased from 1.07% of IMPU-1 to 18.11% of IMPU-11 and the residue at 285℃ was reduced from 97.01% of IMPU-1 to 91.84% of IMPU-11.