Abstract: Reserve growth that is used to evaluate the incremental potential of recoverable reserves in discovered oil?gas fields is a major component of remaining oil and natural gas resources. According to the study of the influencing factors and growth potential of reserve growth in Halfayah oil field, it is found that the factors include geological factor, engineering factor and economic factor. The reserve growth of Halfayah oilfield in 2010—2012 is composed of the discovery of new pool (contributing 7%), the incremental OOIP (51%) and the incremental EOR (42%) in discovered reservoirs. And the extension of the field in the future could allow the reserve growth to be added about 7 956.5×104 t. According to the analogy analysis with Majnoon oilfield, it is believed that the recovery factor of Halfayah field will reach to 32%, and the reserve growth potential will add about 0.98×108 t