Abstract: The heavy oil in Chunguang oilfield is characterized by high viscosity,complex fluid property and big difficulty in production and hydrocarbon transmission.For effective development of heavy oil,the effect of temperature and water cut on fluid properties of heavy oil and yield stress was studied.The results indicated when the water cut was smaller than 40%,with the increase of water cut,the viscosity rose sharply,which was in accordance with the Richarson empirical formula.There was no significant effect of water cut on fluid types in Chunguang oilfield and the rheological properties of Newtonian fluid properties were presented.At 60℃,the heavy oil presented non-Newtonian fluid property of thinning shear.In70℃~90℃,viscosity of heavy oil was not affected by the change of shear rate of Newtonian fluid properties.With the temperature rose,the yield stress value decreased sharply.The higher temperature was a key factor to gurantee the flow property in the formation and the wellbore.