Spawning. Blaze spawners can be found only in Nether fortresses and will start spawning blazes once a player gets within 16 blocks. The mob spawners have a chance of spawning 1-4 blazes at once. Blazes can only spawn in light level 11 or lower (at the lower half of their body).
In Minecraft, you can find blazes in the Nether. Blazes are created from a blaze spawner in the Nether fortress. If you are having trouble finding a blaze, you can also summon a blaze using a cheat or you can use a spawn egg.