This article summar izes several methods for pre- treating the raw material of 1, 3, 5- trimethy-l benzene. The continuous four- tower distillation chart, continuous two-tower distillation chart and batch distillation apparatus are discussed. A new pretreating method is introduced for the extraction rectification by using continuous six- tower chart, which takes account of the factors of both technology and economic benefit, suggesting a new way of saving energy in the production of 1, 3, 5- trimethy-l benzene.