Abstract: The relationship between the apparent viscosity of watered oil and its water cut, temperature and shear rate is studied and the oil in Daqing Oilfield is taken as an example. The result shows that the apparent viscosity of watered oil is the function of the temperature, water cut and shear rate. Before the phase transition point, the apparent viscosity of oil increases with the increase of water cut, and temperature and shear rate have great effects on it. The apparent viscosity at the point decreases distinctly with the increment of shear rate. After the phase transition point, the apparent viscosity of it decreases with the increment of water cut, and temperature and shear rate have also effects on it. Using neural network to simulate the relationship between the apparent viscosity of watered oil and its effect factors, the formula of calculation the apparent viscosity of watered oil is established. With this way, temperature, shear rate and water cut are taken into account and the model is very precision. The study of this paper establishes a foundation for calculating precisely pipeline technological parameter.