Modular precast wall panels and wall construction methods combining dry and wet processes, pertaining to the field of prefabricated building technology, address the issue of combining dry and wet processes in wall panels. The present wall panels include concrete panels with steel mesh, with steel side frames on both sides of the concrete panels. These steel side frames have flanges for forming cast-in-place joints, with the ends of the horizontal reinforcement passing through the bottom plates of the corresponding side steel frames within the concrete panels. During wall assembly, the steel side frames are connected according to the drawings to form cast-in-place joints, completing the dry connection. The horizontal reinforcement of the various prefabricated wall panels in the cast-in-place joints achieve a reserve-type mutual anchoring connection, and self-compacting concrete is poured into the joints to form steel tube concrete columns, completing the wet connection. This invention enables rapid positioning and installation of wall panels, enhances the strength and durability of the joints, and achieves the combination of dry and wet processes during wall assembly, boasting high construction efficiency.