Three radioactive waste incineration facilities have been built in China. The first one has been in operation for more than ten years. Some problems, such as corrosion and waste water treatment in the flue gas cleaning system, have been found in the long time operation of the first facility. According to the origin of the problems, technical process and equipment material of the flue gas cleaning system have been improved in design and been adopted by the second facilities in China. The results showed that most of the problems were resolved, and the improvement is successful.