The invention discloses a reagent and kit for enriching breast cancer stem cells from breast cancer cell strains. The reagent includes galantamine and lycorine as a screening agent. The breast cancer cell strains are MCF-7 breast cancer cell strains. The kit comprises a double-antibody, galantamine and lycorine as a screening agent, a screening-agent-dissolving auxiliary agent, sodium sulfite as an anti-oxidant, a recombinant human epidermal growth factor (EFG) which is a conventional growth factor, bovine serum albumin (BSA), insulin and B27. The provided reagent can enrich breast cancer stem cells from human breast cancer MCF-7 cell strains in a convenient, fast and efficient way, the cell spheroids are short in forming period, and the content of cancer cells and SP cells marked by CD44<+>CD24<- / low> molecules in microsphere cells is high. The developed kit can improve the efficiency for enriching cancer stem cells by science researchers.