The reduction conditions of thermodynamics and dynamics of molybdenum oxide in BOF steelmaking process by using molybdenum oxide direct reduction alloying to replace adding molybdenum iron alloying during tapping are analyzed. And the 110t BOF commercial experiment to steelmaking B7 steel (/% : 0.38 〜0.48C

0.15 ~25 Mo) and steel 42CrMoA (/% : 0.38 ~0.45C

0.15 ~0.25Mo) has been carried out. The results show that the molybdenum yield by BOF molybdenum oxide direct reduction alloying is about the same by adding molybdenum iron alloying during tapping

i. e. about 95%

and with using molybdenum oxide direct reduction alloying the steelmaking cost decreases markedly

the melting cost per ton steel decreases by about 22 yuan.