Because the heavy oil emulsion is opaque and it is impossible to intuitively understand the influence of sand particles on the stability of heavy oil emulsions, some scholars have detected the asphaltenes adsorbed on the surface of mineral particles by Fourier transform infrared spectroscopy. It is speculated that these particles destroy the strength of oil/water interfacial film due to the adsorption of asphaltenes on the oil/water interfacial film and promote the aggregation of water droplets,Sso as to realize demulsification and stratification of heavy oil emulsion.SHowever, this understanding cannot explain some phenomena in our experiment. In this paper, experiments such as bottle experiment, rheology test and wettability test are carried out, and the influence mechanism of quartz sand on the stability of heavy oil emulsion is obtained: when the sand particle size is small and the water droplet particle size is large, the phenomenon of water droplets completely wetting and wrapping the sand particles will occur, the proportion of water droplets wrapping the sand particles will increase, and the settlement speed will accelerate,SThis is the main reason for the demulsification and stratification of heavy oil emulsion by sand, and this understanding is also verified by the sedimentation experiment of sand in white oil.