The magnetic and electronic properties of strontium titanate with different carbon dopant configura-tions are explored using first-principles calculations with a generalized gradient approximation (GGA)and the GGA+ U approach.Our results show that the structural stability,electronic properties and magnetic properties of C-doped SrTiO3 strongly depend on the distance between carbon dopants.In both GGA and GGA+ U calculations,the doping structure is mostly stable with a nonmagnetic fea-ture when the carbon dopants are nearest neighbors,which can be ascribed to the formation of a C-C dimer pair accompanied by stronger C-C and weaker C-Ti hybridizations as the C-C distance becomes smaller.As the C-C distance increases,C-doped SrTiO3 changes from an n-type nonmagnetic metal to ferromagnetic/antiferromagnetic half-metal and to an antiferromagnetic/ferromagnetic semiconductor in GGA calculations,while it changes from a nonmagnetic semiconductor to ferromagnetic half-metal and to an antiferromagnetic semiconductor using the GGA+ U method.Our work demonstrates the possibility of tailoring the magnetic and electronic properties of C-doped SrTiO3,which might pro-vide some guidance to extend the applications of strontium titanate as a magnetic or optoelectronic material.