This study was aimed to explore the anti-leukemic effect of scutellaria extract SBX in human leukemia cell lines and its mechanism. The leukemia cell lines, including HL-60, NB4, U937, K562 and Jurkat, were cultured in vitro and proliferative inhibition of these cell lines was detected by CellTiter-Glo Luminescent Cell Viability Assay in order to screen the most sensitive cell line. The effect of SBX on cell cycle was analyzed by flow cytometry and the protein expressions determined by Protein Pathway Array respectively. The results indicated that SBX (10 - 200 µmol/L, for 72 h) significantly inhibited the proliferation of different leukemia cell lines in a dose-dependent manner (r value was 0.86, 0.88, 0.95, 0.94, 0.96, respectively), the HL-60 was the most sensitive cell line. Flow cytometric analysis showed that SBX (50, 10 µmol/L, for 48 h) arrested HL-60 cells in the G(0)/G(1) phase. In addition, protein expression of p-PKC α/βII, p-p38, Cdc25B, XIAP of HL-60 cells increased, and p-AKT, p-SAPK/JNK, Notch4, Cdk4, Cdc2, cyclin E, Akt, Bcl-2, Bax, cdc42, TNF-α, p27, CaMKKa decreased after exposure to SBX (50 µmol/L, for 48 h). It is concluded that SBX can inhibit the proliferation of different leukemia cell lines, and HL-60 is a sensitive cell line. SBX significantly influences EGFR, Ras/Raf/MAPK and Notch signaling pathway, through which effects the expression of cell cycle-related proteins resulting in arrest of HL-60 cells in G(0)/G(1).