〔Abstract〕 Objective To preliminarily explore the phenomenon and mechanism of apoptosis induced by microsecond pulsed electric field in hepatocellular carcinoma cells HepG2. Methods CCK-8 was used to test the effects of microsecond pulsed electric fields with different parameters on the proliferation of human hepatocellular carcinoma cells HepG2 and human normal hepatocytes L-O2. The effects of microsecond pulsed electric field ablation on HepG2 cell apoptosis under different electric field intensities were observed by flow cytometry; morphological changes of ablated HepG2 cells were observed by transmission electron microscopy; differentially expressed genes between ablated and control cells were screened by transcriptome sequencing and bioinformatics analysis, and the RNA and protein expression of differentially expressed genes in HepG2 cells after pulse ablation was verified by quantitative real-time PCR(qPCR) and Western blot. Results CCK-8 experiments showed the proliferative and inhibitory abilities of microsecond pulsed electric field ablation on hepatocellular carcinoma cells HepG2 and human hepatocytes L-O2 increased gradually with the increase of electric field intensity. However, there was no significant difference in the ablation ability of microsecond pulsed electric field between HepG2 cell and L-O2 cell. When the voltage was increased to 1 600 V/cm, the microsecond pulsed electric field significantly induced apoptosis in HepG2 cells compared to control group, with an apoptosis cells ratio of nearly 80%(P<0.000 1). Using transmission electron microscopy, it was found that the HepG2 cell membrane was fragmented, the mitochondria were irregular in morphology and typical apoptotic vesicles appeared after microsecond pulsed electric field ablation. Transcriptomics analysis showed the major genes revealed to be involved in microsecond pulse ablation were thousand and one amino acid protein kinase 1(TAOK1), frizzled protein family receptor 3(FZD3), calpain 10(CAPN10), matrix metalloproteinase 9(MMP-9), and transforming growth factor β-1-induced transcript(TGFB1) and qPCR analysis showed that the differentially expressed genes were mainly involved in the regulation of RNA polymerase II, signaling, and apoptosis after ablation of HepG2 cells by microsecond pulses at 1 600 V/cm, the RNA expression levels ofTAOK1(P<0.05),FZD3(P<0.01) were significantly up-regulated, and the RNA expression levels ofCAPN10(P<0.001),MMP-9(P<0.01), andTGFB1(P<0.05) were significantly reduced in HepG2 cells. Western blot experiments further confirmed that TAOK1 and FZD3 showed an increase in expression levels after microsecond pulse treatment, while CAPN10, MMP-9 and TGFB1 showed a down-regulation of expression levels. Conclusion Microsecond pulsed electric field ablation can effectively promote apoptosis of hepatocellular carcinoma HepG2 cells, and genes such asCAPN10,FZD3may be involved in the regulation of apoptosis of hepatocellular carcinoma HepG2 cells promoted by microsecond pulsed ablation.