A modular lightning surge protection apparatus is applied to a single-phase three-wire power system with a line, a neutral, and a ground. The modular lightning surge protection apparatus includes a substrate, a surge protection unit, a first temperature fuse, and a second temperature fuse. The surge protection unit has a first surge protection element, a second surge protection element, and a third surge protection element to form a wye connection or a delta connection structure. Furthermore, the surge protection unit, the first temperature fuse, and the second temperature fuse are electrically connected on the substrate to form a small-scale modular circuit integration structure.