Abstract: Objective To investigate the effects of hydrogen sulfide（H₂S）on the proliferation and metabolism of human hepatocelluar carcinoma HepG2 cells. Methods HepG2 cells was treated with NaHS at different concentration.The cellular ultrastructure was observed under the inverted phase contrast microscope. Multiparameter such as proliferation index (PI), cell cycle,cell apoptosis and growth inhibition rate was detected by typan blue staining, MTT and flow cytometry (FCM). Results Various concentrations from 5 mmol/L to 10^-4mmol/L of NaHS promoted HCC cell growth and seldom induced cell apoptosis. G1 stage was increased, while S stage was reduced. The effect of NaHS in combination was significant (P<0.05). The most effective concentration of NaHS was 1 mmol/L. Under the concentration of 1mmol/L NaHS, the growth of HepG2 cell was restrained with the increase in the concentration of Tyrphostin 47. Conclusion H₂S may induce the growth of HCC cell, and its mechanism was associated with the activation of mitogen-activated protein kinase.The most effective concentration of NaHS that promote cell proliferation was 1 mmol/L.