The present invention relates to a plasticizer composition, including a lower alkyl-based citrate and a higher alkyl-based citrate at the same time, as citrate, wherein the ratio of a hybrid type to a non-hybrid type and the ratio of the lower alkyl groups to the higher alkyl groups are controlled so that effects are achieved. When applying the plasticizer composition to a resin, stress resistance and mechanical properties can be maintained at an equal or higher level, the migration and volatile loss properties and the plasticization efficiency can be balanced, and the light resistance and heat resistance can be remarkably improved.