High rank order parameters may comprise substantial information about molecular orientational distribution of liquid-crystalline materials. There are few experimental procedures targeted at the determination of high rank order parameters. We suggest a procedure for the determination of order parameters of a spin probe by numerical simulation of electron paramagnetic resonance (EPR) spectra. The procedure is based on revealing the molecular orientation axis of a spin probe. Order parameters < P-2 >, < P-4 >, and < P-6 > of the spin probe in aligned liquid-crystalline polymer have been measured by the suggested procedure. It was shown that the procedure gives more reliable and complete characteristics of molecular order than does polarized UV-visible spectroscopy.