The invention provides a lattice brick with 19 lattices and the lattice hole diameter of 25 mm and a stacking method, and belongs to the technical field of hot blast stoves in the steelmaking process. The lattice brick comprises a regular-hexagonal-prism-shaped brick body, 19 circular through holes, 12 semicircular through holes and 6 1/3-circular through holes. Three circular grooves evenly distributed in the circumferential direction are formed in the upper surface of the brick body. Corresponding circular bosses are arranged on the lower surface of the brick body. When multiple same brick bodies are stacked together, a gap with the size of 8-10 mm is reserved between the edges, making contact, of every two adjacent lattice bricks. The intersecting center of every three adjacent brick bodies serves as the placement center of the corresponding lattice brick on the upper layer, and then the six edges of each lattice brick on the upper layer are distributed on the three corresponding lattice bricks on the lower layer in pairs. The lattice brick has the advantages of being uniform in overall structure and low in manufacturing difficulty.