Spectroscopic analysis of 31 Aquilae

31 Aquilae is the only evolved star for which SMR status was confirmed by Taylor (1991). For this reason, a new determination of the atmospheric parameters and chemical composition of 31 Aql has been made. The observational material consists of high-dispersion coude echelle spectra obtained with a CCD detector and the l-m telescope of the Special Observatory of the Russian Academy of Sciences. The new value of [Fe/H] obtained here is +0.32+/-0.15 dex. This is close to the upper limit of [Fe/H] for dwarf stars belonging to the thin disk of the Galaxy. The value of the Li abundance log A(Li) = 1.35. The value [C/H] obtained here is -0.05 +/- 0.11 dex. Within the errors, solar values of [element/Fe] are obtained for Na, Y, Zr, Pa, La, Ce, Pr, and Nd. The age of 31 Aql and its location in the Galaxy are estimated, and a careful analysis of abundance determination errors is carried out. 31 Aql is found to be in the evolutionary stage in which the convective envelope begins to extend.