We present the first detailed study of the stellar populations of star-forming galaxies at z \sim 1.5 , which are selected by their [ O ii ] emission line , detected in narrow-band surveys . We identified \sim 1,300 [ O ii ] emitters at z = 1.47 and z = 1.62 in the Subaru Deep Field with rest-frame EWs above 13Å . Optical and near-infrared spectroscopic observations for \approx 10 % of our samples show that our separation of [ O ii ] from [ O iii ] emission-line galaxies in two-color space is 99 % successful . We analyze the multi-wavelength properties of a subset of \sim 1,200 galaxies with the best photometry . They have average rest-frame EW of 45Å , stellar mass of 3 \times 10 ^ { 9 } M _ { \sun } , and stellar age of 100 Myr . In addition , our SED fitting and broad-band colors indicate that [ O ii ] emitters span the full range of galaxy populations at z \sim 1.5 . We also find that 80 % of [ O ii ] emitters are also photometrically classified as “ BX/BM ” ( UV ) galaxies and/or the star-forming “ BzK ” ( near-IR ) galaxies . Our [ O ii ] emission line survey produces a far more complete , and somewhat deeper sample of z \sim 1.5 galaxies than either the BX/BM or sBzK selection alone . We constructed average SEDs and find that higher [ O ii ] EW galaxies have somewhat bluer continua . SED model-fitting shows that they have on average half the stellar mass of galaxies with lower [ O ii ] EW . The observed [ O ii ] luminosity is well-correlated with the far-UV continuum with a logarithmic slope of 0.89 \pm 0.22 . The scatter of the [ O ii ] luminosity against the far-UV continuum suggests that [ O ii ] can be used as a SFR indicator with a reliability of 0.23 dex .