Disclosed are a carrier for delivering a negatively charged drug, comprising a cationic lipid represented by formula 1, and a preparation method thereof. Also disclosed is a pharmaceutical composition comprising a negatively charged drug and a cationic lipid represented by formula 1, wherein the negatively charged drug forms a complex with the cationic lipid. The composition can increase the in vivo stability of the negatively charged drug after local or systemic administration and allows the intracellular delivery of the negatively charged drug. Thus, the composition will be useful for improving the therapeutic effect of the negatively charged drug.