Intervention on MDA-MB-231 cell with tetrandrine inhibits the proliferation and induces autophagy through inhibiting the PI3K/AKT/mTOR signaling via upregulating PTEN expression and downregulating p-akt ser473 /akt, p-PI3K/PI3K p110α, p-mTOR ser2448 /mTOR, suggesting tetrandrine may serve as a promising active antitumor drug, by a direct regulation of the PI3K/AKT/mTOR pathway in the triple-negative breast cancer MDA-MB-231 cell. The gene discussed is PTEN; the disease is triple-negative breast carcinoma.