<p>A reusable steel cover plate was introduced into the aluminium alloy/nylon dissimilar materials single sided coaxial resistance spot welding process, to enhance the quality of the welded joints by improving the heat generation and heat distribution patterns during the welding process, and to avoid electrode life degradation caused by the aluminium-copper alloying. The introduction of a steel cover plate shifted the primary heat production area from the copper electrode/aluminium alloy interface to the steel cover plate and copper electrode/steel cover plate interface, resulting in a more uniform temperature distribution on the aluminium alloy workpiece. Nylon melted and spread more on the aluminium alloy surface, thus accordingly, the average peak tensile shear load was expanded from 2.6 kN to 4.1 kN, with an enhancement of 57.7% at a welding current of 7.5 kA.</p>