<p>An infrared thermal imager and a digital microscope are employed to observe the spreading behavior of oil droplets that are subject to various temperature fields in this study. The spreading characteristics of oil droplets are analyzed by adjusting the temperature field, temperature gradient, liquid viscosity and volume. Experimental results show that when an oil droplet is placed on a solid surface that is subject to a temperature field, the oil droplet always spreads forward in the opposite direction of the temperature gradient. During the spreading process, the front end of the droplet advances while the rear end remains fixed, forming an oil film whose shape is constrained by the temperature field. Moreover, when the temperature field keeps unchanged, a larger temperature gradient will cause the droplet to spread more rapidly, expand the oil film area and promote the morphological evolution. Furthermore, as the viscosity increases, the spreading velocity decreases, and the response of the droplet to the temperature field weakens, resulting in a reduction in the oil film area and suppression of the shape evolution. Finally, the spreading velocity rises with the increase of droplet volumes, and the oil film area expands while preserving morphological similarity. A theoretical model for the spreading speed is established based on the force analysis, and the theoretical results agree well with the experimental values. These findings contribute to the understanding of wear mechanisms caused by lubricant depletion or starvation in mechanical equipment and provide a guide for preventing lubricant accumulation.</p>