A preparation method of a toner having a micro diameter includes: blending a monomer and a dispersing agent in distilled water to prepare a monomer dispersion; polymerizing the monomer dispersion by adding a first polymerization initiator to about 1% by volume to about 50% by volume of the monomer, to cause a first polymerization; mixing the remaining monomer dispersion with the polymerized solution; and polymerizing the mixed solution by adding a wax emulsion and a second polymerization initiator, to cause a second polymerization. The present invention may be advantageously used for obtaining spherical, uniformly micro sized toner particles through the emulsion polymerization only, without performing the aggregation or melting process.