The study was undertaken with the objective to modelling of temperature and relative humidity under polyhouse with different treatment of fanpad system, combination of fanpad with fogger system for shadenet screen and without shadenet screen. The experiment was conducted at Plasticulture farm of the College of Technology and Engineering (CTAE), Udaipur for modelling of microclimate parameters and reference evapotranspiration under polyhouse. The experiment was carried during 05 October 2013 to 06 July 2014 for different treatments of fanpad system, combination of fanpad with fogger system for shadenet screen and without shadenet screen. During experiment temperature and relative humidity was measured for 24 points inside polyhouse from 10:00 AM to 5:00 PM. Pan evaporation was measure during 18 July 2013 to 17 July 2014 inside polyhouse for modelling of evaporation and reference evapotranspiration inside polyhouse. The inside climatic data of temperature, relative humidity wind speed and solar radiation were collected using Automatic Weather Station installed inside polyhose during 18 July 2013 to 17 July 2014 to model evaporation and reference evapotranspiration models.