Potassium salts-catalyzed steam gasification of petroleum coke for H-2 production was performed using a laboratory fixed-bed reaction system with an on-line quadruple mass spectrometer. The gasification reactivity and H-2 production characteristics of petroleum coke-steam gasification catalyzed by potassium salts were investigated mainly. The potassium salt catalysts could not only enhance effectively the gasification reactivity of petroleum coke, but also promote greatly the H-2 production. The catalytic action of various potassium salts was ordered as K2CO3 > KAc > KNO3 > K2SO4 > KCl. The increasing catalyst loading could promote the H-2 production of petroleum coke gasification. However, different potassium salts almost had no effect on the distribution of product gases. It was feasible to produce syngases with high H-2 (up to 60%) and no virtual CH4 (below 0.1%) through the catalytic steam gasification of petroleum coke at relatively low temperatures.