In this paper, Path-integral Monte Carlo calculations have been performed to study structure and superfluid behavior of para-H2 clusters(number of molecules N≤40).Energy difference and superfluid fractions at T=0.4 K and 1.6 K were compared to explore quantum melting of para-H2 clusters. We discussed the interplay between quantum localization and quantum melting of para-H2 clusters, and the differences between quantum localization and superfluidity of para-H2 and ortho-D2 clusters at T = 0.4 K.