Abstract: Potassium nitrate was added to intensify the chromite decomposition process by KOH sub-molten salt. The effects of the mass ratio of alkali-to-ore，the mass ratio of KNO3-to-ore，oxygen partial pressure，gas flow rate and reaction temperature on the decomposition of chromite ore were experimentally studied to determine the chromite decomposition parameters by KOH-KNO3 binary sub-molten salt. The results showed that reaction temperature and the ratio of alkali-to-ore were most significant factors on the chromium conversion efficiency. The effects of oxygen partial pressure and flow rate were less significant. The ratio of KOH-to-ore decreased from 4∶1 to 2∶1 after adding KNO3 to KOH sub-molten salt. The kinetics equation of chromite decomposition was“1+2(1－x)－3(1－x)2/3=kt”，and the apparent activation energy was 55.63 kJ/mol，which agreed with the inner-diffusion control model. KNO3 played a significant role in oxygen transfer，which obviously promoted the decomposition of chromate ore.