  In this paper, the $P-V$ criticality and Joule-Thomson Expansion of
Hayward-AdS black holes in 4D Einstein-Gauss-Bonnet gravity are studied in the
extended phase space. We find the black hole always exhibits a phase transition
similar to that of the Van der Waals system for any arbitrary positive
parameters $\alpha$ and $g$. We also study the dependence of $\alpha$ and $g$
on the inversion curves and plot the inversion and isenthalpic curves in the
$T-P$ plane, which can determine the cooling-heating regions.
