Nanocomposite coating surfaces were electrodeposited on copper substrate at various current densities, deposition times and Al2O3 concentration to experimentally investigate the enhancement of boiling heat transfer of HFE-7100 under atmospheric pressure in a distributed jet array impingement. The surface structure topography and wettability were analyzed to explore their relation to boiling heat transfer enhancement and critical heat flux (CHF). An increase in both current density and deposition time led to a decrease followed by an increase in the wettability of the Cu– Al2O3 surface. Conversely, an increase in Al2O3 concentration resulted in decreased surface wettability. However, unlike pool boiling, jet impingement attenuated the impact of enhanced surface wettability on boiling heat transfer and CHF; instead, the microstructure on the surface was found to be closely linked to boiling heat transfer performance. The nanocomposite coating surfaces exhibited a 70 % higher maximum boiling heat transfer coefficient and 50 % higher CHF than those of smooth surfaces. Excessive Al2O3 concentration weakened the enhancement of heat transfer performance due to the inhibitory effect of Al2O3 nanoparticles on copper growth, leading to reduced micro-nano structures.