Abstract: In consideration of the limitations of single factor evaluation method, by using orthogonal test, the performance of paraffin inhibitor under the joint actions of temperature, shear strength and action time was discussed, and the interaction among these factors was analyzed. Moreover, the mechanism of paraffin inhibitor under different experimental conditions was analyzed in aspects of lattice parameters and micro morphology of wax crystal. Results show that temperature difference and shear strength have more significant effects than action time on paraffin inhibition rate. There are interactions among temperature difference, shear strength and action time, but the interactions are not distinct. By changing the diffraction peak intensity, ordering and interplanar spacing of wax crystal, the paraffin inhibitor can make the wax crystal grow more regularly, become larger and develop into quasi-spherical, so as to inhibit the wax deposition.The factors have different impacts on wax crystal structure after paraffin inhibitors added, but they all work by changing the diffraction peak intensity and interplanar spacing of wax crystal.