Based on the hydrogeological characteristics of field site contaminated by the petroleum in the Northeast of China, the effects of environmental factors on the growth of microorganisms and the biodegradation of benzene and xylene are investigated by batch experiment. Also, the migration rules for microorganisms in different sandy media and the biodegradation of benzene and xylene using biosparging are carried out by column experiment. The results indicate that the optimal condition for the biodegradation of benzene and xylene is as follows: the temperature is 20℃, pH value is 7.0, nitrogen and phosphorus added and DO is 5.21mg/L. The migration velocity of microorganisms increases with the diameter and porosity of the media increasing. For one kind of medium, the time for microorganism penetrating first medium of 20cm is longer than last medium of 20cm. For different media, the time taken by microorganisms to penetrate the medium of 40cm is in an ascendant order, namely, gravelly sand<coarse sand<medium sand. Generally speaking, with the diameter of the media decreasing, the removal rate of benzene and xylene increases and in the medium of medium sandy, the removal rate reaches at above 40% by biosparging.