Abstract: Heavy oil of the Tahe oil field has a high viscosity, high density, high content of gum and asphalt. Asphaltene deposited frequently when heavy oil mixed with condensate oil, which blocks storage tanks and ground pipelines. In view of the influencing factors on the stability of oil colloid and combined with colloid stability theory, we mixed Tahe heavy crude oil and condensate oil in different proportions. The compatibility of mixed samples was analyzed using spot experiments, and some qualitative conclusions were made. Quantitative data have been obtained by the determination of mixed crude oil stability parameters. We determined a reasonable ratio range of the two kinds of crude oil, which provided theoretical guidance for effectively solving the problem of blending and transportation of different oils.