Abstract: The traction coefficients of 4106 aviation lubricating oil were measured at various normal loads, rolling speeds, lubricant inlet temperatures, and slide to roll ratios, on a ball disk traction rig. The traction behavior of the oil was analyzed and a new formula to calculate the traction coefficient was established. It was found that the tested oil showed significant non Newtonian characteristics and there existed a critical normal load at which the traction coefficient assumed a transition with increasing normal load. The thermal effects in the contact zone became more prominent at a relatively lower lubricant oil inlet temperature. The higher the normal load, the smaller the effect of the lubricating oil inlet temperature and rolling speed on the traction coefficient. Moreover, the prediction results based on the established formula agreed well with the experimental ones. Thus the establish formula could be applied to guide the dynamics design of rolling bearings.