This paper surveys the physical properties of the multiwall carbon nanotube (MWNT) and polyurethane composite film for improvement of mechanical properties and electrical characteristics. The modification of MWNT was carried out by acid treatment with nitric and sulphuric acid mixed solution, and then followed by thermal treatment for enhancing MWNT dispersion with polyurethane. This modified MWNT was mixed with polyurethane by changing the loading content of MWNT and dispersion time under the dimethylformamide solution in the ultrasonic wave apparatus. Various physical characteristics of the modified PU/MWNT films were measured and analyzed in terms of the loading content and dispersion time. The maximum absorbance of the PU/MWNT films were observed with the 2wt% loading at dispersion times of 2 and 24 hour, respectively. The minimum electrical volume resistivity of PU/MWNT film was shown at the loading content of 0.5wt% or more irrespective of dispersion treating time. However the optimum condition was assumed to 2wt% loading at dispersion time of 2 hours by assessing the surface profile of the film using video microscope. The breaking stress and strain of the PU/MWNT film decreased with increasing loading content, but no change of physical properties was shown with increasing in dispersion time.