  In this paper, we study compactifications of the moduli of smooth del Pezzo
surfaces using K-stability and the line arrangement. We construct K-moduli of
log del Pezzo pairs with sum of lines as boundary divisors, and prove that for
$d=2,3,4$, these K-moduli of pairs are isomorphic to the K-moduli spaces of del
Pezzo surfaces. For $d=1$, we prove that they are different by exhibiting some
walls.
