Growth of lithium niobate large plate crystals was achieved by using the Wet-ted-Die Technique. Their dimensions were about 200 mm long, 20 mm in width and 3 mm thick. Their properties was found to be the same as those of cylindrical crystals. We measured the density ρm of the melt of lithium niobate and its surface tension a. The results are: ρm= 3.57×103kg/m3, α = 204 dyne/cm at 1270℃, and ρm= 3.42×103kg/m3, α = 192 dyne/cm at 1300℃.