Abstract: Abstract: This paper is devoted to the study of main geological factors affecting SAGD development of oil sand in Canada and defining key geological parameters for reserve quality evaluation based on the performance in SAGD development. It is revealed that the key parameters for reserve quality evaluation include HPVH, Facies1 percentage and Sw. Criteria are established for defining each parameter mentioned above. There are three types of reserves. The type I is the reserve with HPVH higher than 6 m³/m² and Facies1 percentage more than 70%, the type III is that with HPVH less than 4 m³/m² and Facies1 percentage less than 70%, and the type II are those having the parameters between the typeⅠand type Ⅲ. The typeⅠcould be further divided into 2 sub-types based on Sw. The results mentioned above can be taken as the foundation of reserve quality evaluation, and used as the basis for well placement in un-development areas during SAGD production.