The present invention relates to a composition for preventing, treating, and alleviating cancer comprising melittin nanoparticles having high targeting to cancer and a long half-life in blood. The present invention provides the composition for preventing and treating cancer comprising: a core comprising melittin; and particles comprising a coating layer covering the core.본 발명은 암에 대한 표적성이 높고 혈중 반감기가 긴 멜리틴 나노입자를 포함하는 암 예방, 치료 및 개선용 조성물에 대한 것이다.