Abstract: The change of rheology for Daqing crude oil treated with PPD during the process of wax deposition simulation and the main factors influencing the wax deposition of the oil are studied and investigated. The wax deposition model for the oil is established with regression equations through experimental results. The influence of 8-31 PPD on the wax deposition of the oil is emphatically studied. The two important conclusions are obtained on the basis of comparison and analysis on the test results of wax deposition between Daqing blank crude oil and the oil treated with PPD.