Moiré superlattices in van der Waals heterostructures, arising from lattice mismatch or twist angle, provide a powerful platform for engineering correlated electronic and excitonic states. Moiré excitons form when electrons and holes are individually modulated by the moiré potential yet remain bound by Coulomb interaction, resulting in exciton wavefunctions with a highly nontrivial and rich real-space structure. However, achieving in situ and dynamic control over the interplay between excitonic Coulomb interaction and the moiré potential remains a central challenge. Here, we demonstrate that hydrostatic pressure provides a continuous and effective means of enhancing the moiré potential and tuning moiré excitons in WSe2/WS2 moiré heterobilayers. As pressure increases, intralayer moiré excitons exhibit systematic redshifts as the moiré potential deepens. Crucially, above ~3 GPa the system enters a strong-moiré regime, where a new higher-energy intralayer moiré exciton emerges that is not accessible otherwise. Combining dual-gate optical spectroscopy with Bethe-Salpeter equation calculations, we reveal that this emerging moiré exciton state arises from strong pressure-induced hybridization between two distinct exciton series: Wannier- Rydberg (WR) and charge-transfer (CT) excitons. Enhanced exciton-electron and exciton-exciton interactions observed in doping-dependent photoluminescence further evidence the strengthened moiré potential under pressure. Our work establishes a pioneering paradigm of moiré excitonic wavefunction engineering, enabling the on-demand creation of tailored excitonic species in moiré superlattices.