Abstract: Selection is carried out for an optimal condition of the bioremediation of soil contaminated by Daqing crude oil and simulating mediation experiments are conducted in engineering scale under the optimal condition. Results show that within the three contaminated concentration areas chosen, Total Petroleum Hydrocarbons (TPH) contented in the highly contaminated soil are removed most; the removal rate of TPH in the soil in initial mediation stage is higher and the degradation rate of TPH in the soil in late stage goes mildly. TPH removal rate in the soil within 60 days achieves 80% and that after 7 months reaches up to 99%. The experiments indicate that optimal effect can be obtained using the bioremediation technology to mediate the soil contaminated by Daqing crude oil under suitable conditions.