A flat fluorescent lamp with discharge uniformity is provided. The lamp includes a first substrate and a second substrate having discharge electrodes; a sidewall corresponding to a frame of any one of the two substrates; and a plurality of serpentine shaped discharge channels defined by the sidewall, first barrier ribs, and second barrier ribs, and having serpentine shaped widths corresponding to horizontal pitches between the left/right sidewall and the first barrier rib and between the first barrier ribs, and having discharge channel widths corresponding to vertical pitches between the second barrier ribs, wherein the serpentine shaped discharge channel is varied in length depending on its position within the flat fluorescent lamp.