The present invention relates to a composition for reducing localized fat without a pain, edema, and side effect, and a method for preparing the same. More specifically, the present invention relates to a composition comprising glycocholic acid (or a salt thereof) or taurocholic acid (or a salt thereof) and phosphatidylcholine (PPC) at a particular mixing ratio for reducing localized fat without side effects such as a pain, edema, necrosis of muscle cells, fibroblasts and vascular endothelial cells other than adipocytes, anesthesia of administration sites, extensive swelling, erythema, induration, paresthesia, nodule, pruritus, burning sensation, nerve injury, and dysphagia, and a method for preparing the same.The DCA single injectable preparation or PPC injectable preparation in which DCA is mixed as a solubilizing agent, which is the conventional injectable preparations for reducing localized fat, has been known to accompany such side effects as a pain, anesthesia, extensive swelling, localized edema, erythema, induration, paresthesia, nodule, pruritus, burning sensation, dysphagia, and the like due to necrosis of cells caused inevitably by lysing not only adipocytes but also fibroblasts, vascular endothelial cells and skeletal muscle cells. Thereby, patients have been complaining of pain, discomfort and anxiety, with low compliance. On the other hand, the injectable composition for reducing localized fat according to the present invention is a safe and stable formulation, selectively lyses adipocytes, and has an excellent effect on inducing apoptosis of adipocytes, so that it is an excellent composition improving the compliance and quality of patients life without above-mentioned side effects.