The utility model relates to the technical field of thick-thin separation combustion. The utility model relates to a burner, in particular to a primary air nozzle structure of a rich-lean burner. Outlet end abrasion can be effectively relieved; extending service life, the device comprises a primary air nozzle, a partition plate is mounted at the outlet end of the primary air nozzle; wherein a partition plate is arranged in the primary air nozzle and divides the primary air nozzle into an upper-layer thick side outlet and a lower-layer thin side outlet, at least two louver blades are arranged in the primary air nozzle, and the anti-abrasion device is characterized in that an anti-abrasion stop block is arranged at the upper end of the inner wall of the upper-layer thick side outlet, and aninclined plane with a Ni coating is arranged on the anti-abrasion stop block facing one side of the flue gas inlet.