Abstract: Supply of adequate quantities of fresh potable water is one of the most serious problems confronting human. To resolve this crisis, solar distillation is a typical process where solar energy is used to distil fresh water from saline or brackish water for drinking purposes and other applications. It is generally classified into passive and active distillation systems. This study proposed a new solar plate-fin distillation system that was designed to increase the productivity and improve the efficiency of the solar plate-fin still. The solar still worked by virtue of the higher evaporation rate under vacuum conditions. A mathematical model was developed and used to optimize the design of the heating cell. Also, presented and discussed in a detail description of local and average heat transfer characteristics of the serrated fins. Results indicated different structure of heating cell has a significant effect on the characters of the new solar plate-fin desalination unit.