This article examines the effect of the concentration of a surfactant on the rheological properties of Algerian crude oil, when the yield stress, the apparent viscosity, the pressure drop and flow rate are evaluated. The surfactant choice is Toluene; different concentrations (2%, 3% and 6%) are tested to improve the transportation capacity of Algerian crude oil. The rheological tests are carried out using the rheometer AR2000 from TA Instruments with a coaxial cylindrical geometry type Couette. Because of large contact surface of the cylinder, one can obtain a good accuracy of the measurements at low viscosity values. Different temperatures were tested. The experimental results show that the rheological behavior of system (crude oil / Toluene) exhibits a non-Newtonian behavior at a low shear rate It was also noted that the increase in the surfactant concentration has an effect on the rheological parameters, the apparent viscosity, yield stress significantly decreased with the addition of toluene. The results obtained also show that the increase in the concentration of the additive also has an effect on the transport capacity of the crude oil, the addition of 6% of toluene has increased the flow rate of the crude oil by 44%.