Suspension polymerization toner of a core-shell structure with dense charges comprises core-shell composite particles prepared by mixing suspension dispersion liquid of toner core particles with shell monomer emulsion and resin-type CCA dispersion liquid, and carrying out a polymerization reaction to form rigid shell layers with dense charges coated on the soft toner core particles. A preparation method thereof comprises: mixing a low-Tg monomer oil phase forming toner core particles with aqueous dispersion liquid, carrying out a heating polymerization reaction after suspension granulation to convert monomer oil droplet particles to polymer particles, and obtaining soft toner core particles; adding a high-Tg shell monomer forming rigid shell layers into water containing a surfactant to form emulsion, adding the emulsion and CCA dispersion liquid into suspension dispersion liquid of the soft toner core particles for second polymerization after mixing, and cleaning, filtering, drying and performing additive treatment.