In the process of oilfield development, the formation of emulsion between crude oil and water is quite common, which increases the difficulty of crude oil treatment. The composition of crude oil, especially the precipitation of paraffin wax, has significant influence on the stability of the emulsion. From the unique perspective that the oil composition affects the phase change and then further determines the emulsion stability, a systematic study was carried out with the methods of emulsion stability test, oil-water interfacial characteristic test, wax precipitation test, asphaltene dispersion stability test, and microscopic observation. It is observed that increasing the amount of liquid paraffin in the solvents leads to a change in the form of wax crystals from fine particles to larger agglomerated wax crystals, and the asphaltenes dispersion stability decreases along with it. Test temperature can significantly affect emulsion stability. At 30 °C, increasing the percentage of liquid paraffin reduces the interfacial tension, increases the interfacial dilatational modulus, and enhances the structure of the interfacial film. This contributes to the formation of small droplets and improves emulsion stability to a certain extent. At 15 °C, by contrast, increasing the liquid paraffin content promotes the development of a more structured wax crystals network, which significantly enhances emulsion stability by binding water droplets. Additionally, it is also found that a wax crystal interfacial film could be formed at the surface of the emulsified drops, which improves further the interfacial film strength and emulsion stability. Based on the above findings, an influencing mechanism model is presented concerning the synergistic stabilization of model oil emulsion containing asphaltene and paraffin wax.