Provided are a polymer capsule loaded with transition metal particles having excellent water dispersibility and stability, and a method for preparing the same. Specifically, the polymer capsule loaded with transition metal particles according to the present invention includes a surface-modified polymer capsule surface-modified to thereby have a positive zeta potential in a dispersed state in water; and transition metal particles loaded on a surface of the surface-modified polymer capsule. In addition, a method for preparing a polymer capsule loaded with transition metal particles according to the present invention includes a) preparing a polymer capsule; b) surface-modifying the polymer capsule to prepare a polymer capsule having a positive zeta potential in a dispersed state in water; and c) sequentially adding a water-soluble transition metal precursor and a reducing agent to a water dispersion of the surface-modified polymer capsule obtained in step b).