Ethanolamine (EA, including MEA, DEA and TEA) is a kind of heat sensitive material. It is easy to be colored at high temperature which influences the product quality and its application. This paper studies the relationship between color number and time of MEA, DEA, TEA and their mixtures at different temperatures. The result shows that MEA is most sensitive to high temperature, TEA take the second place, DEA is almost unaffected. DEA can protect TEA and MEA from being colored, the more DEA content, the better effect. According to the results of tests and process simulation, optimized parameters of separation equipment and operation are put forward which can provide guidance for the production of high purity, low color number of TEA.