Abstract: In order to effectively transport high-viscosity heavy oil at normal temperature, a heavy oil emulsifying experiment was carried out to analyze the effect laws and mechanisms of the type and mass fraction of surfactant and organic alkaline on the stability and rheology of heavy oil O/W emulsions. And water diversion rate and viscosity reduction rate were taken as the main evaluation indexes of the experiments. It is shown that different types of surfactants are structurally different, so they are different in the adsorption on oil-water contact and the heavy oil emulsifiying capacity. When surfactant OP-10 and organic alkaline(EDA, TEOA and TIPA)are compounded, synergistic effect is generated. And there is an optimum mass fraction in the compounded system of surfactant OP-10 and TEOA, beyond which the emulsion will become unstable instead. Then, 0.75% OP-10-0.25% TEOA binary system was selected as the optimal system after water diversion rate, viscosity reduction rate, economy, safety and environmental protection were considered comprehensively. The emulsion prepared from the optimal system has long-term stability and anti-hard water capacity, and its water diversion rate in 24 h is 29.8%. When the molar concentration of the Ca²⁺ is 0.02 mol/L, the water diversion rate in 6 h is 19.4%. The research results provide the theoretical basis and technical guidance for the application of heavy oil emulsifying and viscosity reducing transportation technology.