Abstract: Microbial degradation is a technology for remediating alkanes in petroleum-contaminated soil. However, it is susceptible to environmental conditions and has low remediation efficiency. To find a method to enable soil microorganisms to effectively degrade alkanes in the long term, a study on the degradation of alkanes in soil by pre-oxidation combined with a microbial activator was carried out, in which Fenton reaction was used for pre-oxidation, and the microbial activator consisted of a combination of glucose and acetic acid. The study examined the effects of petroleum-contaminated soil microbial quantity, respiration activity, and population changes on alkanes biodegradation by four different treatments: activated group (pre-oxidation and activator), non-activated group Ⅰ (activator only, without pre-oxidation), non-activated group Ⅱ (pre-oxidation only, without activator), and control group. The results showed that the half-life of alkanes in the activated group was only 64 days, which was 333 d shorter than that in the non-activated group Ⅱ. The biodegradation rate of alkanes remained high for a long time, and the biodegradation rates at each stage were 14.23% (0-20 d), 17.93% (20-40 d) and 15.73% (40-60 d), respectively. The degradation of alkanes in every 20 d maintained above 1 500 mg/kg. However, the biodegradation rates of alkanes in the other three groups decreased significantly over time, and the highest degradation rate of alkanes was only 5.50% at 40-60 d. The fluorescence standard integration volumes of humic-like and fulvic-like acids in the soil after pre-oxidation were 2.80 and 3.82 times higher than those before soil pre-oxidation, respectively, which promoted the rapid growth of soil microorganisms. After adding acetic acid and glucose, the soil microorganisms were activated, and the activator utilization rates reached 88.06% and 91.38%, respectively. The soil microbial respiration activity remained above 5.00 mol/kg, while the non-activated group had a maximum of only 2.12 mol/kg at 40-60 d. In addition, the number of petroleum degrading bacteria in the activated group exceeded 9.00 lg(CFU/g) in the later stage, forming five dominant genera: Bacillus, Pseudomonas, Microbacterium, Streptomyces, and Hydrogenophaga, while the non-activated group had at most three dominant genera. The study indicated that the long-term degradation of alkanes in soil by microorganisms was mainly driven by their respiratory activity, abundance of petroleum-degrading bacteria, dominant genera number, and nutrient utilization rate. The research results provide an economical and effective method for solving the problem of soil petroleum pollution.