AbstractStar formation rate (SFR) is one of the most important diagnostics in understanding the evolution of galaxies across cosmic times. In order to explore the possibility of using the optical u-band luminosities to estimate SFRs of galaxies, we show the correlations between u band, Hα and infrared luminosities by combing the data from the South Galactic Cap u band Sky Survey (SCUSS) with the Sloan Digital Sky Survey (SDSS) and the Wide-field Infrared Survey Explorer (WISE). We derive the u versus Hα relation and the u and 12 μm relations to calibrate the u-band luminosity as an SFR indicator.