Based on hydraulic principle, the hydraulic cavitation device was self-made. And the Fluent software was employed to simulate the distribution of internal fields, such as pressure, flow velocity and steam holdup in the Venture tube installed in the device, where the degradation process of simulated phenol wastewater was strengthened by adding Fenton reagent. The effects of cavitation time, inlet pressure, solution pH and initial phenol concentration on the degradation of phenol were investigated. The results showed that the highest degradation ratio of 55.74% was achieved under the conditions of 60 mg/L initial phenol concentration, 3.0 pH value, 0.4 MPa inlet pressure and 120 min cavitation time. Under the combination of hydrodynamic cavitation and Fenton reagent in the presence of H₂O₂ concentration of 120 mg/L, Fe²⁺ concentration of 30 mg/L and cavitation time of 120 min, the degradation ratio of phenol reached to 96.62%, which were 40.88% and 55.65% higher than that obtained under hydraulic cavitation or Fenton reagent alone respectively. Kinetic studies indicated that the degradation of phenol was approximately the first order reaction, and the calculated enhancement factor f was 2.46. Finally, the Xinjiang Yihua actual coal gasification wastewater was tested by combined using the hydraulic cavitation device and Fenton reagent. The results displayed that when the sample was treated for 60 min and 120 min, the corresponding of phenol/COD degradation ratios were 72.9%/78.6% and 78.3%/84.2%, respectively.