Molecular distillation is a special liquid-liquid separation technology. It is different from traditional distillation by the principle of boiling point difference separation, but by the difference of the average free path of the molecular motion of different substances to achieve separation. When the liquid mixture flows along with the heating plate and is heated, light and heavy molecules will escape the liquid surface and enter the gas phase. Due to the different free paths of light and heavy molecules, the molecules of different substances will move at different distances after they escape from the liquid surface. After passing through the condensation tube in the main evaporator, light molecules reach the condensation tube and are discharged, while heavy molecules cannot reach the condensation tube and are discharged along with the mixed liquid. In this way, the purpose of material separation is achieved.