A preliminary study on potential of very large scale photovoltaic power generation systems (VLS-PV) in deserts from economical and environmental view points has been studied. However, the data in the studies depend on site, country, price and so on. Therefore, a sensitivity analysis of the studies should be obtained. In this paper, five case studies of sensitivity analysis of VLS-PV systems were evaluated from economical and environmental view points. Case studies were set five cases; (1) PV module efficiency, (2) PV module degradation, (3) interest ratio and depreciation period, (4) labor cost and (5) cable. In summary, generation cost was affected by degradation, interest ratio, depreciation period and labor cost. Required energy and CO2 emission were affected by PV module efficiency and degradation ratio