Abstract: The characteristics of components of heavy oil, their interactions and effects on the wax deposition behavior of heavy oil from Yumen oil field were studied by using chromatogram separation, Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and optical microscope. The results indicate that the interaction between the components can inhibit the precipitation of wax crystal effectively. The behaviors of A₁ with different polarity components added are quite different from that of the heavy oil. The wax-appearing temperature, the peak temperature of wax-precipitation and the percentage of precipitated wax are decreased. The optical microscope analysis shows that the addition of resin and asphaltene to A₁ can increase the number of wax crystal particles and decrease their dimensions during the cooling crystallization process, which can prevent the particles from contacting and crosslinking each other to form bulk wax crystal aggregation.