Objective To explore the mechanism of ropivacaine induced apoptosis in a human colorectal cancer (CRC) SW620 cell line via the mitochondrial pathway. Methods Human CRC SW620 cells were cultured in vitro and treated with ropivacaine. The viability of cancer cells was determined by CCK-8 assay. CRC cells were divided into CRC cell, low-dose, medium-dose, and high-dose ropivacaine groups. Referring to the CCK-8 assay result , CRC cells in the low-dose, medium-dose, and high-dose ropivacaine groups were treated with 20, 50, and 100 μg / mL ropivacaine, respectively. The mitochondrial membrane potential (MMP) in each group was detected by flow cytometry. The expression of apoptosis proteins (Bcl-2, Bax, caspase-3, caspase-9) was detected by western blot. The cell cycle and apoptosis of CRC SW620 cells were determined by flow cytometry. Results The CCK-8 assay showed that with an increase in ropivacaine dose, the inhibition rate of human CRC SW620 cells was significantly increased, and the lethal dosage 50 (LC50 ) was approximately 69. 36 μg / mL. The apoptosis rate in the CRC cell group was 1. 52 ± 0. 11%, which was significantly lower than that in the low-dose, medium-dose, and high-dose ropivacaine groups ( 35. 91±5. 69%, 46. 27± 6. 57%, 69. 36±8. 01%, respectively; F= 559. 203, P<0. 001). Compared with the CRC cell group, the MMP, ratio of cells in G2 / M phase, ratio of cells in S phase, and the relative expression level of Bax protein were significantly and dose- dependently decreased in each group treated with ropivacaine (P<0. 001), whereas the ratio of cells in G0 / G1 phase, and the relative expression levels of Bcl-2, caspase-3, and caspase-9 proteins were significantly and dose-dependently increased (P<0. 001). Conclusions Ropivacaine promoted the apoptosis of human CRC SW620 cells via the mitochondrial pathway and the action mechanism may involve signal transduction related to caspase-3 and Bcl-2.