Based on the analysis of the mechanism of the falling film evaporation and the falling film condensation, a new solar desalination system with three effect regeneration was made. The simulation experiment of the system was worked out in the steady condition, the fresh water yield rate and performance radio under the different temperatures was given. According to the experimental results, not only the dynamic simulation matching of solar collection system was researched, but also design parameter of the whole system was optimized and the improving design was provided in the paper. At last, the other effluence factors on the fresh water yield rate was researched and analyzed. Their reasonable range was given.