Abstract: Electrical conductivity (EC) is an important parameter of nutrient solution management. In order to investigate the effects of EC on photosynthesis rate and dry matter production of greenhouse cucumber, experiment of greenhouse cucumber with different EC was conducted in greenhouse of Jiangsu University from September 2009 to July 2010. Effect of different EC on leaf area, maximum photosynthesis rate and dry matter production were quantitative analyzed. A simulation model based on thermal and photosynthetically active radiation was founded. Independent experimental data were used to validate the model. The results showed that the coefficient of determination between simulated and measured values of leaf area index, maximum photosynthesis rate and dry matter production based on the 1:1 line were 0.89, 0.93 and 0.94, respectively. And root mean squared error between the simulated and measured values were 0.21 m2/m2, 1.52μmol/(m2·s) and 36.77 kg/hm2, respectively. Relative error between the simulated and measured values were 4.5%、11% and 9.2%, respectively. The model could be used for optimizing nutrient solution management for greenhouse cucumber.