Abstract: Based on the assumption of equal degree of substitution or equal number ofsubstituents on aromatic ring,the aromatic ring distribution of heavy oils and bitumens is es-timated by NMR proton spectra on the aromatics with the different ring number.Band as-signments of aromatic protons are checked with model mixtures. In this way the aromaticring distributions of four Alberta asphaltenes are estimated. The results show that the effectof the assumption above-mentioned on the error of the ring distribution estimate is insignifi-cant,and the content of aromatic condensed rings of Alberta asphaltenes is not high,whichis different from the traditional estimates.