Abstract: To optimize dehydration process of Canada SAGD oil sand emulsion, experiment was made on physical properties of Canada SAGD oil sand samples, and theoretical analysis was made on stability of SAGD oil sand emulsion. In the experiment, two typical diluents were used to identify their respective behaviors in dilution dehydration, providing direction for the perfection and optimization of dehydration process. The experimental results show that the economic-technical ratio of aromatic diluting solvent represented by naphtha is 20%; although the naphtha has good effect on reducing viscosity and increasing differential density, its effect on waterdrop coalescene is unobvious, resulting in poor dehydration effect, therefore, demulsifier is still needed in practical application. In contrast, the aliphatic solvent represented by normal heptanes, with higher viscosity and density than naphtha, has less effect on viscosity reduction; however, when exceeding a certain proportion, it can make the asphaltene in SAGD oil sand emulsion deposit, with dilution characteristics converted from viscosity reduction into asphaltene sedimentation. The experimental results show that, when the diluent ratio reaches 1.8, the waterdrop in oil sand emulsion can be completely removed.