The low dispersion (400A/mm) spectrum of the optical counterpart of a flat-spectrum radio source 87GB 080315.5+512613, which is one of two possible radio counterparts of 2EG J0809+5117, was obtained recently. The optical counterpart, which is 2:0200 away from 87GB 080315.5+512613 and 19:30 away from 2EG J0809+5117, was identied as a quasar with redshift of 1.14.We noted that Mattox et al. (1997) suggested the other radio counterpart 87GB 080459.4+495915 (OJ 508), which is 87:10 away from 2EG J0809+5117, is the more potential identication, though it was previously suggested to be the identication (with low condence) of another nearby EGRET source 2EG J0807+4849. Our observation suggests that it is quite possible that 87GB 080315.5+512613 is the identication of 2EG J0809+5117 rather than 87GB 080459.4+495915. But we still can not exclude the possibility of 87GB 080459.4+495915 at present. Moreover, in order to determine whether or not 87GB 080315.5+512613 is a blazer type quasar, the optical polarization and variability measures of its optical counterpart are strongly encouraged.