You can do it in either transmittance or reflectance mode depending upon the sample's transparency. http://mcf.tamu.edu/instruments/uv-vis-nir-spectrophotometer. Transmittance mode is more easily available. Try to cast your sample as thin as possible to analyze in transmittance mode.

Thank so much for your response. But as you know the transmittance analysis using uv-vis spectrophotometer needs a dilute solution and you speeking about casting sample. so we need firstly to dissolve the sample then determine the transmittance at fixed wave length. Can you give me the details.

Do you want to determine the absorption spectra ? The absorption spectrum of polyethylene is in vacuum-ultaviolet spectral region at about 1780, to 1050 Å.