Method of purifying particle

A method of purifying a particle, comprising a plurality of following steps:

• preparing a purification solution, wherein the purification solution comprises a first purification solution and a second purification solution, and the first purification solution and the second purification solution are immiscible with each other;
• fully mixing a mixed solution to be purified with the purification solution, and letting stand until a plurality of separated layers appear, wherein the mixed solution to be purified comprises a particle modified by a ligand, a free-state ligand, and a dispersant, a dispersion degree of the particle modified by the ligand in the first purification solution is greater than a dispersion degree of the particle modified by the ligand in the second purification solution, and a dispersion degree of the free-state ligand in the first purification solution is greater than a dispersion degree of the free-state ligand in the second purification solution;
• removing a layer of liquid where the second purification solution is located, and extracting a layer of liquid where the first purification solution is located;
• and
• freezing and drying the extracted layer of liquid to obtain a purified particle.