The invention provides a lightweight partition board with a net rack and fiber-reinforced hollows and a splicing method thereof, and relates to the prefabricated partition boards of assembly type concrete structures in the field of architectural industrialization. The lightweight partition board comprises a board body, steel wire meshes, obliquely inserted bars, positioning grooves and cavities, wherein the obliquely inserted bars are fixedly connected with the upper steel wire mesh and the lower steel wire mesh to form the space net rack, the board body is formed by casting through ceramsite fiber concrete, and the upper surface and the lower surface of the board body are formed into natural rough surfaces through special formworks with foveolate protrusion structures. According to the lightweight partition board with the net rack and the fiber-reinforced hollows and the splicing method thereof, the problems that an existing partition board is prone to cracking, low in strength and high in water absorption are solved, the factory prefabrication can be achieved, the self weight is low, the flexible connection with a main body can be achieved, shock resistance can be better achieved, the construction is quick, the manufacturing cost is low, energy conservation and environment protection are achieved, safety and reliability are achieved, and sound insulation and heat preservation effects are good.