Exosome for inhibiting invasion of triple negative breast cancer cells as well as preparation method and application of exosome

The invention discloses an exosome for inhibiting invasion of triple negative breast cancer cells as well as a preparation method and application of the exosome. The exosome is obtained by purifying umbilical cord mesenchymal stem cells according to a specific culture condition and a specific passage mode, has an effect of remarkably inhibiting invasion of triple negative breast cancer cells at a specific concentration, and has a wide application prospect in the aspect of treating cancers such as breast cancer. The umbilical cord mesenchymal stem cell is prepared by the following preparation method: step S1, passage and culture of umbilical cord mesenchymal stem cells: 10% of fetal calf serum without exosomes needs to be added into a culture medium of the umbilical cord mesenchymal stem cells, a used culture flask needs to be a T175 cell culture flask, and the passage proportion needs to be 1: 4; step S2: exosome purification: purification is carried out through an ultra-high speed centrifugation method, the