The present invention relates to a plasticizer composition including a lower alkyl-based citrate and a higher alkyl-based citrate simultaneously as citrates, wherein effects are achieved through controlling the ratio of hybrid and nonhybrid types, and the ratio of lower alkyl and higher alkyl, and if the plasticizer composition is applied in a resin, stress resistance and mechanical properties may be maintained to the equal or better levels, balance between migration and loss properties, and plasticization efficiency may be achieved, and light resistance and heat resistance may be markedly improved.