The mercury release during pyrolysis of eight Chinese bituminous coals under N-2 at temperatures up to 1200 degrees C was studied. The pyrolysis experiment was carried out in a quartz reactor. Results show that higher than 93% of mercury release out during pyrolysis. The release of mercury from all the coals begins at about 150 degrees C with two or three mercury peaks at the similar temperature range. The correlation analysis shows that mercury in the coals has close relation with the mineral and the mercury released at different peaks is mainly correlated with different types of material in the coals. The first peak located at 150-400 degrees C is mainly correlated with carbonate mineral as well as organic material in the coals. The second peak located at 500-600 degrees C is mainly correlated with sulfide minerals in the coals. The third peak located at higher than 750 degrees C is mainly correlated with aluminosilicate mineral in the coals. A large part of mercury in coal can be removed by pyrolysis below 400 degrees C.