Abstract: This research investigated the effect of parthenolide on the proliferation and migration of human breast cancer cells and explored the molecular mechanism of that effect. Surface plasmon resonance and fluorescence resonance energy transfer melting were used to detect the binding and stabilizing ability of PTL and G-quadruplex. MTT assays were used to determine the effect of PTL on the proliferation of MCF-7 breast cancer cells. A wound healing assay was performed to detect the migration of MCF-7. The results indicate that PTL shows good binding and stabilizing activities with c-myc G-quadruplex with a K_D=13.1 μmol·L^-1. PTL inhibited the proliferation of MCF-7 cells with an IC₅₀ of 21.3 μmol·L^-1 (24 h), 14.5 μmol·L^-1 (48 h) and 9.1 μmol·L^-1 (72 h). PTL inhibited MCF-7 breast cancer cell proliferation and migration and down-regulated the transcription and expression level of c-myc by targeting G-quadruplex.