In this paper, we prepared the nanoparticle drug carrier system between nanoparticles — chitosan and Epigallocatechin-3-O-gallate (EGCG) for breast cancer cell inhibiting application. For this drug carrier system, chitosan acts as a carrier and EGCG as a drug. Which were systematically characterized and thoroughly evaluated in terms of their inhibition rate and biocompatibility. We also did a cell scratch test and the result indicated that the chitosan-EGCG nanoparticles have inhibitory effect on the growth of breast cancer cells. The inhibition rate could reach up to 21.91%. This work revealed that the modification of nanoparticles paved a way for specific biomedical applications.