Abstract: Traction measurements for HKD-1 aviation lubricating oil were carried out, using a ball-disc machine. This paper presents an approach to determinate Erying stress and pressure-viscosity coefficient of lubricant in elastohydrodynamic lubrication based on the data of non-linear ascending region of a traction curve. Erying stresses and pressure-viscosity coefficients of aviation lubricating oil were analyzed and new formulae for calculation were provided. Results show that approach for determinating Erying stress and pressure-viscosity coefficient is appropriate and simple, formulae for calculating are well precise and can be used into dynamic behavior design of bearings. Erying stress increases and pressure-viscosity coefficient decreases with an increase in contact pressure, inlet temperature and rolling velocity. Effects of rolling velocity on Erying stress and pressure-viscosity coefficient are less significant than those of contact pressure and lubricant oil temperature.