Objective To investigate the relation between gaseous signal molecule hydrogen sulfide (H2S) and diseases. Methods Literatures about the advancement of H2S were reviewed and analyzed. Results H2S is recognized as a novel gaseous signal molecule. By acting specially on ＫATPchannels, H2S can relax smooth muscle cells to regulate blood pressure.It even plays an important roles in pulmonary hypertension, ischemia/reperfusion injury, neurotransmission， apoptosis and inflammatory reaction. Conclusion H2S has been regarded as the third gaseous signal molecule， which exerts many physiological and pathological effects on mammals, and will pave way for development of new drugs and provide therapeutic intervention for various diseases.