Abstarct: The evaporative cooling systems are being considered from early days due to their advantages. The low initial cost of installation and low cost of use, easy and inexpensive maintenance and fresh air supply in the building are the most important advantages of such systems. the impossibility of using these systems in wet climates is one of the disadvantages about evaporative systems. evaporative cooling systems are compatible with the environment and are used as a system for ventilation of the environment within buildings. In the present study, the evaporative cooling system was studied and modeled, using desiccant absorbents. the system is designed using a desiccant wheel, heat exchanger to air, cooling and air heater. In the rotating wheel, the intake air flow is dry by removing the moisture from it. moisture has increased the percentage of moisture on the surface of desiccant and then the accumulated moisture stored in the desiccant material is absorbed by the flow of the recovery air and sent out. The dry air from the desiccant wheel enters a heat exchanger to reduce the amount of its temperature, so as to prepare to enter the cooler at the dew point. The air then enters the coolant to reach the desired temperature for the desired space. Also, the flow temperature returning from the internal environment, by passing the heat exchanger into the air and the heater, reaches the temperature required by the desiccant wheel and then enters the wheel. In this study, cooler system is evaluated with mathematical modeling of a solid desiccant wheel, with mass and energy balances and momentum for air and moisture present in the desiccant material for process and recovery air flow. the results showed that the intensity of moisture during the desiccant wheel depends on the moisture flow rate, the velocity of the inter wheel, the thickness of the desiccant material, the hydraulic diameter of the wheel and the temperature. Also, according to the efficiency of cooler to dew point, the lower the temperature of the incoming air, the outlet temperature is closer to the desired temperature for the considered space. The results of this study, obtained by using the climate of lahijan County, indicate that the designed system is able to minimize the flow of ambient air with 37 °C and 70 % moisture to 24 ° C with 26 % moisture for the space considered.