Pyroptosis is a caspase 1-dependent programmed cell death. Various pathological stimuli could trigger formation and activation of a multiprotein complex called the inflammasome, leading to the activation of caspase 1. A combination of downstream processes such as plasma-membrane pore formation, release of multiple activated inflammatory cytokines and DNA cleavage mediated by caspase 1, would eventually result in cell osmotic lysis which would release intracellular proinflammatory contents and induce a special programmed cell death intermediate between apoptosis and necrosis named pyroptosis. Pyroptosis is a conserved cell death process mediating inflammation and immune responses. To explore the molecular mechanism of pyroptosis and elucidate how inflammasome activates caspase 1 within pyroptosis will offer us some new targets to prevent and cure complicated immune diseases such as sepsis and inflammatory bowel disease.